JP6997659B2 - Measuring method and measuring device - Google Patents

Description

The present invention relates to a measuring method and a measuring device.

Conventionally, in a measuring device that calculates hematocrit using the electrical resistivity of blood, which is an example of a biological sample (also referred to as a biological sample), and the relational expression between the electrical resistivity of the filtrate and the hematocrit, the blood and the filtrate It is known that the electrical resistivity of the above is corrected by these temperatures (for example, Patent Document 1). Further, there is a sample temperature measuring method for measuring the temperature of a sample by applying a predetermined voltage to the temperature electrode, which is less affected by the increase or decrease of the sample analyte (measurement target component) (for example, Patent Document 2, Patent Document 2, 2. Patent Document 3).

Japanese Unexamined Patent Publication No. 58-29450 Japanese Patent No. 4876186 Japanese Patent No. 5092021

It is an object of the present invention to provide a method for measuring the temperature of a sample using a new method, and a measuring device.

One aspect of the present invention is to use an analytical tool that includes a reagent that reacts with a biological sample, a plurality of electrodes, and a flow path of the reagent and the sample in which the plurality of electrodes are arranged. It is a measurement method for measuring temperature. In this measuring method, two electrodes selected from the plurality of electrodes including the electrode provided with the reagent are used, and the first voltage from the electrode provided with the reagent in the sample in the flow path is used. A step of applying the above, a step of measuring the first response current value of the sample with respect to the first voltage, and the above two electrodes selected from the plurality of electrodes and not provided with the above reagent. A step of applying a second voltage to the sample in the flow path, a step of measuring the second response current value of the sample with respect to the second voltage, and a step of the first response current value and the second response current value. It is characterized by including a step of determining the temperature of the sample based on the correspondence relationship between the value relatively indicating the relationship with the first response current value and the second response current value. do.

Another aspect of the invention is the sample using an analytical tool comprising a reagent that reacts with a biological sample, a plurality of electrodes, and a flow path of the reagent and the sample in which the plurality of electrodes are arranged. It is a measuring device that measures the temperature of. This measuring device uses two electrodes selected from the plurality of electrodes, including the electrode provided with the reagent, and the first voltage from the electrode provided with the reagent in the sample in the flow path. Using the first measuring unit for measuring the first response current value of the sample with respect to the first voltage, and two electrodes selected from the plurality of electrodes and not provided with the reagent. A second measuring unit that applies a second voltage to the sample in the flow path and measures the second response current value of the sample with respect to the second voltage, the first response current value, and the second response. Includes a calculation unit that calculates the temperature of the sample based on the correspondence between the value relatively indicating the relationship with the current value and either the first response current value or the second response current value. It is characterized by that.

According to the present invention, the temperature of a sample can be measured by a new method.

1 (A) is a top view of the analytical tool (biosensor having 4 electrodes) according to the embodiment, and FIG. 1 (B) is a side view of the analytical tool shown in FIG. 1 (A). FIG. 2 shows a modified example of the electrode configuration of the analysis tool (a biosensor having three electrodes). FIG. 3 shows a configuration example of the measuring device according to the embodiment. FIG. 4 is a flowchart showing an example of a measurement method using the analysis tool and the measuring device according to the embodiment. 5 (A) to 5 (D) show the measurement results in Example 1-1. 6 (A) to 6 (D) show the measurement results in Comparative Example 1. 7 (A) to 7 (D) show the measurement results in Example 1-2. 8 (A) to 8 (E) show the measurement results in Examples 1-3. FIG. 9 shows the results of Example 2-1. FIG. 10 shows the results of Example 2-2. FIG. 11 shows the results of Comparative Example 2-1. FIG. 12 shows the results of Comparative Example 2-2.

Hereinafter, the measuring method and the measuring device according to the embodiment will be described. In the embodiment, the temperature of the sample is measured using an analytical tool including a reagent that reacts with the biological sample, a plurality of electrodes, and a flow path of the sample in which the reagent and the plurality of electrodes are arranged. The measuring method and the measuring device to be performed will be described.

The measuring method according to the embodiment is to use two electrodes selected from the plurality of electrodes, including the electrode provided with the reagent, from the electrode provided with the reagent in the sample in the flow path. The step of applying the voltage of 1 is included. The measuring method further comprises a step of measuring the first response current value of the sample with respect to the first voltage, and using two electrodes selected from the plurality of electrodes and not provided with the reagent. It includes a step of applying a second voltage to the sample in the flow path and a step of measuring the second response current value of the sample with respect to the second voltage. The measuring method further comprises a value that relatively indicates the relationship between the first response current value and the second response current value, and one of the first response current value and the second response current value. Includes a step of determining the temperature of the sample based on the correspondence.

The degree of influence of the above-mentioned first response current value by the temperature of the sample is different from the degree of influence of the above-mentioned second response current value by the temperature of the sample. The inventor of the present invention has a temperature that corresponds to a value that relatively indicates the relationship between the first response current value and the second response current value and either the first response current value or the second response current value. It has been found that it is dependent and exhibits a suitable resolution for making a temperature determination. Therefore, for example, by acquiring calibration curve data showing the relationship (correlation) between the correspondence and the temperature in advance and converting the correspondence of the measured sample into temperature based on the calibration curve data, the sample is sampled. The temperature of the can be measured. However, it is not always necessary to acquire the calibration curve data in advance.

Here, the value that relatively indicates the relationship between the first response current value and the second response current value is a value that indicates the relationship between the first response current value and the second response current value in comparison between the two (hereinafter,). It is referred to as “relative value”), and is, for example, the ratio (quotient) or difference between the first response current value and the second response current value. However, the relative value is not limited to the above-mentioned ratio or difference as long as it is a value that relatively indicates the relationship between the first response current value and the second response current value. Further, the correspondence between the relative value and any one of the first response current value and the second response current value is, for example, the first response current value and the second response current value in the graph represented by two axes. One of the two axes is one of the two axes (for example, the Y axis (vertical axis)), and the relative value between the first response current value and the second response current value is the other of the two axes (for example, the X axis (horizontal axis)). It is a point on the graph when it is done. The correspondence relationship includes a relationship in which the corresponding first response current value or second response current value is uniquely (uniquely) determined when the relative value is determined. However, it is not essential to create a graph for showing the correspondence relationship, and only a value obtained by simply calculating the other from one of the relative value and the first response current value or the second response current value may be used. In addition, the method of calculating the correspondence can be appropriately adopted.

An analytical tool applied to the measuring method is, for example, a biosensor. Biological samples are liquid samples such as blood, interstitial fluid, and urine. The components to be measured in the sample are glucose level (blood glucose level), lactate value (lactic acid level) and the like. In addition, the characteristics in the sample are the hematocrit value, viscosity, salt concentration and the like of blood.

The two electrodes used for measuring the first response current value (used for applying the first voltage) are, for example, from an electrode to which a voltage is applied (working electrode) and an electrode paired with the working electrode (counter electrode). Become. The reagent may be provided only on the working electrode or on both electrodes (working electrode and counter electrode). Here, "the reagent is provided on the electrode" means a state in which the reagent is placed in contact with the electrode, a state in which the reagent is fixed, or a state in which the reagent is placed. Further, although no reagent is provided at the working electrode and the counter electrode, the case where the reagent is provided between the working electrode and the counter electrode also applies to "two electrodes used for measuring the first response current value". "The reagent is provided between the working electrode and the counter electrode" means that the reagent is placed in contact with the substrate between the working electrode and the counter electrode, and the flow path between the working electrode and the counter electrode. This includes the state where the reagent is placed in contact with the spacer or cover that forms the reagent (for example, the reagent is not placed on the substrate, but the reagent is opposite to the working electrode when the flow path is viewed in a plan view. If it is in between). In other words, "a reagent is provided between the working electrode and the counter electrode" means that the installed reagent is diffused (moved) to the measurement environment near the working electrode due to the influence of the sample introduced into the flow path. It means that it is provided so that it can be done. However, in order to obtain a value in which the first response current value accurately reflects the result of the reaction between the sample and the reagent, the value of the first voltage is increased as compared with the case where the reagent is provided on the working electrode. Additional conditions are required, such as lengthening the application time and lengthening the measurement time so that the reagent diffuses onto the working pole in the flow path. From the above, in the measurement of the first response current value, it is necessary to provide a reagent on the working electrode or between the working electrode and the counter electrode. On the other hand, when the reagent is not provided on the working electrode or between the working electrode and the counter electrode, and the reagent is provided on the counter electrode, it does not correspond to "two electrodes used for measuring the first response current value". Further, even if the reagent is provided between the working electrode and the counter electrode, if the reagent diffuses only in the vicinity of the counter electrode and does not diffuse in the measurement environment near the working electrode, the reaction between the reagent and the sample is the first response current. Since it does not affect the value, it does not apply to "two electrodes used for measuring the first response current value".

Further, regarding "two electrodes used for measuring the second response current value", no reagent is provided on both of the two electrodes. Further, regarding the two electrodes (for example, the working electrode and the counter electrode) used for measuring the second response current value, no reagent is provided at the working electrode and the counter electrode, but a reagent is provided between the working electrode and the counter electrode. The working electrode and counter electrode of the case do not apply to "two electrodes used for measuring the second response current value". That is, in the measurement of the second response current value, it is necessary that the reagent is not provided not only in the working electrode and the counter electrode but also in all the measurement environments of the second response current value. The absence of reagents in all measurement environments means that no reagents are present in the path of electrons (current flowing between the working electrode and the counter electrode) that travels between the working electrode and the counter electrode through the sample. means. In other words, the second response current value does not include any value due to the reaction between the sample and the reagent.

The plurality of electrodes include two electrodes used for measuring the first response current value described above, and an electrode that can be used as two electrodes used for measuring the second response current value. 1st response current value measurement and 2nd
An electrode without a reagent may be commonly used between the response current value and the measurement. In other words, of the two electrodes to which the first voltage is applied, the electrode different from the electrode provided with the reagent is one of the two electrodes not provided with the reagent to which the second voltage is applied. May be. Further, a part or all of the plurality of electrodes may be used for measuring the characteristics of the sample (for example, the hematocrit value of blood) or a predetermined component to be measured (for example, glucose) in the sample. Here, the temperature of the sample affects the response current value when a predetermined voltage is applied. That is, it affects the identification of samples such as hematocrit value (also referred to as Hct value) and the measurement of measurement target components such as glucose level (also referred to as blood glucose level) based on the response current value when a predetermined voltage is applied. give. Therefore, by correcting the Hct value, glucose value, etc. using the measured temperature of the sample, it is possible to obtain the measurement result (concentration of the measurement target component, etc.) of the measurement target component of the sample with high accuracy. In this embodiment, an example of applying the measured temperature of the sample to the correction of the Hct value and the glucose value will be shown below. However, the application of the measured temperature is not limited to these, and can be changed according to the component to be measured using the analytical tool and the like.

The plurality of electrodes can be composed of, for example, one electrode provided with at least a reagent and two electrodes not provided with a reagent (three-electrode configuration). In this case, one of the electrode provided with the reagent and the two electrodes not provided with the reagent can be commonly used for the measurement of the first response current value. However, different electrode pairs may be used for the measurement of the first response current value and the measurement of the second response current value (four-electrode configuration). In these 3-electrode configuration and 4-electrode configuration, 2 electrodes may be selected from 4 electrodes and used in common as an electrode pair for measuring a predetermined measurement target component in a sample. Further, for example, a 5-electrode configuration including three electrodes used for measuring the first and second response current values and two electrodes for measuring a predetermined measurement target component in the sample may be adopted. A 4-electrode configuration may be used in which one of the two electrodes for measuring a predetermined measurement target component in the sample is used in common with one of the three electrodes. Further, for example, a 6-electrode configuration including two sets of electrode pairs (4 electrodes) used for measuring the first and second response current values and two electrodes for measuring a predetermined measurement target component in the sample is adopted. It may be a 5-electrode configuration that is commonly used with one of the four electrodes. The combination of electrodes forming the above-mentioned 3 to 6 electrode configurations can be appropriately set as long as the first and second response current values and the measurement target component can be measured.

Further, it is possible to adopt a configuration in which the characteristics of the sample, for example, the hematocrit value of blood are measured by using two electrodes included in the plurality of electrodes and not provided with the reagent. In the case of the hematocrit value of blood, the electrode for measuring the hematocrit value is common to the two electrodes used for measuring the second response current value, or one of the two electrodes is common to two electrodes. It may be different from both of the electrodes. Further, it may be common with an electrode that is not provided with a reagent used for the two electrodes for measuring the first response current value and measuring a predetermined measurement target component in the sample. When the above-mentioned 6-electrode configuration is used, if one of the two electrodes for measuring the hematocrit value is common, the plurality of electrodes have a 7-electrode configuration. Further, when different from all of the two electrodes, the plurality of electrodes have an eight-electrode configuration. When the first and second response current values, hematocrit values and measurement target components (for example, glucose values) are measured, any of these 3 to 8 electrode configurations may be adopted.

In the measuring method according to the embodiment, the value of the first voltage and the value of the second voltage may be the same, but it is preferable that they are different from each other. The value of the second voltage may be larger or smaller than the value of the first voltage. As described above, the difference between the first voltage and the second voltage makes it possible to obtain better resolution than when both have the same value. In the sample temperature measuring method according to the embodiment, it is preferable to adopt a configuration in which each of the first voltage value and the second voltage value is 1 V or more and 7 V or less.

In the measurement method according to the embodiment, the value of the second voltage is larger than the value of the first voltage (first).
The value of the voltage of is lower than the value of the second voltage). Reagents that react with biological samples and measure the concentration of the sample include salts such as enzymes and substrates. When the same voltage is applied to the electrode provided with the reagent containing the salt and the electrode not provided with the reagent, the reactivity of the sample (sample reacting with the reagent) at the electrode provided with the reagent is determined. Due to the influence of the salt, the reactivity of the sample (sample not reacting with the reagent) on the electrode without the reagent is better and the resolution is higher. If the first voltage and the second voltage are the same voltage, in order to optimize the reaction of the sample at the electrode to which the first voltage is applied, the second voltage is adjusted to the first voltage. Since the voltage will be set, the reactivity of the sample at the electrode to which the second voltage is applied may be insufficient. On the contrary, if the value of the first voltage is increased in accordance with the second voltage in order to make the sample reactive at the electrode to which the second voltage is applied, the first voltage is applied. The reactivity of the sample at the electrodes becomes excessive, which may result in poor resolution. Therefore, rather than setting the same conditions as the first voltage applied to the electrode provided with the reagent and the second voltage applied to the electrode not provided with the reagent, the first voltage is taken into consideration for each reactivity. It is more preferable that the value of the second voltage is larger than the value of the first voltage so that the reactivity according to the value of and the reactivity according to the value of the second voltage are appropriate values.

In the measuring method according to the embodiment, for example, when the sample is blood, it is preferable to use the second response current value as a value indicating the hematocrit value of blood. That is, the measurement result of the second response current value acquired for the temperature measurement may be used as information indicating the hematocrit value. In this case, the two electrodes included in the plurality of electrodes without reagents are used as two electrodes common to the temperature measurement and the measurement of the value indicating the hematocrit value. As a result, the number of electrodes provided in the analysis tool can be reduced, and the analysis tool can be miniaturized. Moreover, since the measurement process can be standardized, the measurement time can be shortened. However, the hematocrit value may be obtained based on the second response current value. For example, the hematocrit value can be obtained by preparing calibration curve data for converting the second response current value into a hematocrit value and converting the hematocrit value from the second response current value.

However, as described above, the two electrodes used for measuring the second response current value may or may not be common to or one of the two electrodes used for measuring the hematocrit value. good. For example, in the sample temperature measuring method according to the embodiment, when the sample is blood, a voltage is applied between the two electrodes to further measure the response current value corresponding to the hematocrit value of blood. May be adopted. In this case, it is preferable that the two electrodes include at least one of the two electrodes selected from the plurality of electrodes and used for measuring the second response current value.

In addition, the following configuration can be adopted in the measurement method according to the embodiment. That is, when the sample is blood, the electrode provided with the reagent among the two electrodes to which the first voltage is applied is directed toward one of the two electrodes to which the second voltage is applied. Further comprising the step of applying a voltage to measure the response current value corresponding to the glucose level in the blood. In other words, it further comprises the step of applying a voltage from one of the two electrodes provided with the reagent toward the other electrode to measure the response current value corresponding to the glucose level in the blood. The configuration may be adopted. In this case, the two electrodes are one electrode selected from the electrode used for measuring the first response current value and the electrode used for measuring the second response current value, and the first response current value selected from a plurality of electrodes. It consists of one electrode other than the electrode used for the measurement of the above and the electrode used for the measurement of the second response current value.

Further, in the measurement method according to the embodiment, the response current value corresponding to the glucose value in blood is measured after the measurement of the second response current value, and the first response is measured after the response current value corresponding to the glucose value in blood is measured. A configuration for measuring the current value can be adopted.

Further, the following configuration may be adopted in the sample temperature measuring method according to the embodiment. That is, the first response current value indicates the current value at a predetermined time point during the first time when the first voltage is continuously applied for the first time, and the second response current value refers to the second voltage. The current value at a predetermined time point in the second time when it is applied continuously for the second time is shown. The predetermined time point in the first time is, for example, the end point of the first time, and the predetermined time point in the second time is the end point of the second time. In this case, the first response current value indicates the current value at the end point of the first time when the first voltage is continuously applied for the first time, and the second response current value is the second voltage. The current value at the end point of the second time when continuously applied for the time of is shown.

[Embodiment]
Hereinafter, the measuring method and the measuring device according to the embodiment of the present invention will be described with reference to the drawings. The configurations of the embodiments described below are exemplary, and the invention is not limited to the configurations of the embodiments.

In the following embodiment, a biosensor, which is an analytical tool, is used as an example of a measuring method and a measuring device, and blood, which is a sample, is used as an example of a sample, and the glucose level as a component to be measured in the blood is measured. A measuring method and a measuring device for correcting the glucose level based on the Hct value in blood and the temperature of blood will be described.

<Biosensor configuration>
1 (A) and 1 (B) show a configuration example of an analytical tool (biosensor) according to an embodiment. 1 (A) is a top view of an analytical tool (biosensor having 4 electrodes) according to an embodiment, and FIG. 1 (B) is a side view of the biosensor shown in FIG. 1 (A).

In FIGS. 1A and 1B, the biosensor 10 has a longitudinal direction (X direction) having one end 10a and an other end 10b, and a width direction (Y direction). The biosensor 10 is formed by laminating and adhering an insulating substrate 1 (hereinafter referred to as “substrate 1”), a spacer 2, and a cover 3 in the height direction (Z direction).

For example, a synthetic resin (plastic) is used for the substrate 1. Examples of the synthetic resin include polyetherimide (PEI), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene (PE), polystyrene (PS), polymethacrylate (PMMA), polypropylene (PP), and polyimide resin. Various resins such as acrylic resin, epoxy resin and glass epoxy can be applied. An insulating material other than the synthetic resin can be applied to the substrate 1. Insulating materials include paper, glass, ceramics, biodegradable materials and the like, as well as synthetic resins. The same material as that of the substrate 1 can be applied to the spacer 2 and the cover 3.

An electrode 11, an electrode 12, an electrode 13, and an electrode 14 are provided on the upper surface of the substrate 1 as an example of a plurality of electrodes. Each of the electrode 11, the electrode 12, the electrode 13, and the electrode 14 has a key shape having a portion extending in the width direction and a portion extending in the longitudinal direction of the biosensor 10, and the portion extending in the longitudinal direction is a lead portion 11a. , A lead portion 12a, a lead portion 13a, and a lead portion 14a. The lead portion 11a, lead portion 12a, lead portion 13a, and lead portion 14a on the one end 10a side are not covered with the spacer 2 and the cover 3, and are used for electrical connection with the connector of the blood glucose meter 20 (FIG. 3). Will be done.

Each of the electrode 11, the electrode 12, the electrode 13 and the electrode 14 is made of a metal material such as gold (Au), platinum (Pt), silver (Ag), palladium (Pd), ruthenium (Ru), or carbon. It is formed using a carbon material such as. For example, each of the electrode 11, the electrode 12, the electrode 13, and the electrode 14 has a metal layer having a desired thickness by forming a metal material by physical vapor deposition (PVD, for example, sputtering) or chemical vapor deposition (CVD). Can be formed as. Alternatively, each of the electrode 11, the electrode 12, the electrode 13 and the electrode 14 can be formed by printing an ink containing a carbon material or metal particles on the substrate 1 by screen printing.

The spacer 2 has a rectangular notch (a concave portion recessed from the other end 10b toward one end 10a) that opens toward the other end 10b side. By stacking the substrate 1, the spacer 2, and the cover 3, the other end 10b side of the biosensor 10 is exposed to the thickness surface of the notch portion of the spacer 2 and the notch portion (covered by adhesion with the spacer 2). A space having an opening 9a formed by the upper surface of the substrate 1 provided with the electrodes and the lower surface of the cover 3 is formed. This space is used as the flow path 9 of the sample. An air hole 7 is formed in the cover 3. The flow path 9 is formed so that the sample spotted in the opening 9a is drawn (introduced) into the flow path 9 by a capillary phenomenon and moves toward the air hole 7 (flows in the flow path 9). Has been done. A part of the electrode 11, the electrode 12, the electrode 13, and the electrode 14 is exposed in the flow path 9. The electrodes 11, the electrodes 12, the electrodes 13, and the electrodes 14 are formed side by side in the order of proximity to the opening 9a. Reagent 8 is provided (fixed) on the electrode 13 and the electrode 14. On the other hand, the electrodes 11 and 12 are not provided with reagents.

Reagent 8 contains an enzyme or a substrate. In other words, it can be said to contain salt. Reagent 8 may also include a mediator. The enzyme is appropriately selected according to the type of sample and the component to be measured. When the component to be measured is glucose in blood or interstitial fluid, glucose oxidase (GOD) or glucose dehydrogenase (GDH) is applied. The mediator is, for example, a ferricyanide, a ruthenium complex, a p-benzoquinone, a p-benzoquinone derivative, a phenazinemethsulfate, a methylene blue, a ferrocene, a ferrocene derivative and the like. Among these, ferricyanide or ruthenium complex is preferable, and potassium ferricyanide or ruthenium compound [Ru (NH ₃ ) ₆ ] Cl ₃ is more preferable.

The electrode 13 and the electrode 14 are used as a pair of electrodes used for measuring the glucose level. As an example, the electrode 13 is used as a working electrode and the electrode 14 is used as a counter electrode. However, the reverse is also possible. Further, the electrode (one of the electrode 13 and the electrode 14) used as a counter electrode in the measurement of the glucose value may not be provided with a reagent. Further, the electrode 11 and the electrode 12 may be used as a counter electrode when measuring the glucose value.

The electrode 11 and the electrode 12 are used as an electrode pair used for measuring the Hct value. As an example, the electrode 11 is used as a working electrode and the electrode 12 is used as a counter electrode. However, the reverse is also possible.

In the examples shown in FIGS. 1 (A) and 1 (B), the combination of the electrode 11 and the electrode 12 in which the reagent 8 is not provided is used to obtain the second response current value. Further, a combination of one of the electrodes 13 and 14 and one of the electrodes 11 and 12 is used to obtain the first response current value. Hereinafter, as an example, an example in which the electrode 13 and the electrode 12 are used to obtain the first response current value will be described. When the reagent 8 is provided only on one of the above-mentioned electrode 13 and the electrode 14, for example, when the reagent 8 is provided only on the electrode 13 among the electrode 13 and the electrode 14, the electrode 13 has a glucose value. It is used as a working electrode in the measurement and the measurement of the first response current value.

The biosensor 10 can also adopt a three-electrode configuration as shown in FIG. FIG. 2 illustrates a biosensor 10A having a three-electrode configuration, wherein the biosensor 10A includes an electrode 15, an electrode 16, and an electrode 17, and is arranged side by side with the electrode 15, the electrode 16, and the electrode 17 in the order of proximity to the opening 9a. The reagent 8 is placed on the electrode 17. In such a three-electrode configuration, Hc
In measuring the t-value, for example, the electrode 15 is used as a working electrode and the electrode 16 is used as a counter electrode. On the other hand, in the measurement of the glucose value, the electrode 17 is used as a working electrode, and the electrode 15 or the electrode 16 is used as a counter electrode. For the measurement of the first response current value, the electrode 17 is used as a working electrode, and the electrode 15 or the electrode 16 is used as a counter electrode. For the measurement of the second response current value, one of the electrode 15 and the electrode 16 is used as a working electrode, and the other is used as a counter electrode. The 4-electrode configuration shown in FIG. 1 (A) and the 3-electrode configuration shown in FIG. 2 are examples, and the 5 to 8 electrode configurations described so far may be applied to the biosensor.

<Configuration of measuring device (glucose meter)>
FIG. 3 is a block diagram showing a configuration example of a glucose meter 20 which is an example of a measuring device. In FIG. 3, for example, the biosensor 10 shown in FIGS. 1A and 1B can be connected to the blood glucose meter 20. The blood glucose meter 20 measures the glucose level using the connected biosensor 10 and corrects the glucose level using the Hct value. In the following description, as an example, the blood glucose meter 20 uses different electrode pairs for measuring the glucose level and the Hct value for the biosensor 10, and the electrode pair without a reagent is provided for the Hct measurement. The case of using it will be described.

The blood glucose meter 20 includes a glucose measuring unit (GLU measuring unit) 33, a hematocrit measuring unit (Hct measuring unit) 34, a measuring unit 35, a switch (SW) 31, a control unit 23, a storage unit 24, and an output unit 25. The switch 31 is electrically connected to a plurality of connectors (connector 32a, connector 32b, connector 32c, and connector 32d in FIG. 2). The connector 32a is connected to the lead portion 11a (electrode 11) of the biosensor 10, and the connector 32b is connected to the lead portion 12a (electrode 12) of the biosensor 10. The connector 32c is connected to the lead portion 13a (electrode 13) of the biosensor 10, and the connector 32d is connected to the lead portion 14a (electrode 14) of the biosensor 10.

The switch 31 is a switch for switching the electrical connection between the connector 32a, the connector 32b, the connector 32c, the connector 32d and the electrode 11, the electrode 12, the electrode 13 and the electrode 14, and the disconnection state thereof. The control unit 23 is a processor (for example, a central processing unit (CPU)) that executes a program stored in the storage unit 24. The storage unit 24 includes a main storage device such as a RAM (Random Access Memory) and a memory including an auxiliary storage device such as a ROM (Read Only Memory) and a hard disk. The storage unit 24 stores a program executed by the control unit 23, data used when executing the program, and the like. The output unit 25 includes an output device such as a printer and a display, and a communication device such as a signal connector and a communication interface.

The control unit 23 controls the SW31 at the time of measuring the glucose level so that the working electrode (electrode 13) and the counter electrode (electrode 14) for measuring the glucose level are electrically connected to the blood glucose meter 20. The electrode 11 and the electrode 12 are cut. The GLU measuring unit 33 is composed of a circuit, a processor, and a memory, and performs the following operations. That is, the GLU measuring unit 33 applies a DC (direct current) voltage (DC voltage for measuring the glucose value) from the electrode 13 to the electrode 14 according to the instruction from the control unit 23. The GLU measuring unit 33 measures the response current value corresponding to the glucose value (hereinafter referred to as GLU response current value) as the response current value to the DC voltage after the application is started and the application is continuous for a predetermined time.

The control unit 23 controls the SW31 at the time of measuring the Hct value so that the working electrode (electrode 11) and the counter electrode (electrode 12) for measuring the Hct value are electrically connected to the glucose meter 20. The electrode 13 and the electrode 14 are cut. The Hct measuring unit 34 is composed of a circuit, a processor, and a memory, and performs the following operations. That is, the Hct measuring unit 34 applies a DC voltage (DC voltage for measuring the Hct value) from the electrode 11 to the electrode 12 according to the instruction from the control unit 23. The Hct measuring unit 34 measures the response current value (hereinafter, Hct response current value) corresponding to the Hct value as the response current value to the DC voltage after the application is started and the application is continuous for a predetermined time.

The measuring unit 35 is composed of a circuit, a processor, and a memory, and performs the following operations according to instructions from the control unit 23. That is, the measuring unit 35 has a DC voltage (first voltage) for obtaining a first response current value when the electrode 11 and the electrode 14 are connected by the SW31 and the electrode 12 and the electrode 13 are in the disconnected state. Is continuously applied for a predetermined time in the direction from the electrode 13 to the electrode 12. At this time, the measuring unit 35 measures, for example, the response current value at the end point (end point) of a predetermined time as the first response current value. However, the measuring unit 35 may acquire the current value at a predetermined time point (timing) during application of the first voltage as the first response current value instead of the current value at the end point of the first voltage application. A combination other than the electrode 13 and the electrode 12 may be used to obtain the first response current value. Even in that case, the first response current value can be measured by continuously applying the current from the electrode provided with the reagent 8 to the electrode not provided with the reagent 8. For example, in the configuration shown in FIG. 1A, it is conceivable to apply the first voltage in the direction from the electrode 14 to the electrode 11.

When measuring the second response current value, the control unit 23 controls SW31 so that, for example, the electrode 11 and the electrode 12 are electrically connected to the glucose meter 20, and the electrode 13 and the electrode 14 are cut off. Put it in a state. The Hct measuring unit 34 applies a DC voltage (second voltage) from the electrode 11 to the electrode 12 according to the instruction from the control unit 23. The Hct measuring unit 34 measures the response current value with respect to this DC voltage as the second response current value after the application is started and the application is continuous for a predetermined time.

As described above, in the blood glucose meter 20 according to the embodiment, the Hct measuring unit 34 and the electrodes 11 and 12 used for measuring the Hct value can be used for measuring the second response current value. Therefore, the step of measuring the Hct response current value and the step of measuring the second response current value can be shared. That is, the Hct response current value may be measured as the second response current value. In this case, the voltage for measuring the Hct value becomes the second voltage for measuring the second response current value. Further, a part of the step of measuring the Hct response current value may be common to the step of measuring the second response current value. For example, by standardizing the procedure for applying the DC voltage and acquiring the second response current value at a timing different from the acquisition timing of the Hct value, some standardization is realized. Of course, a configuration may be adopted in which the step of measuring the Hct value and the step of measuring the second response current value are individually performed by using the Hct measuring unit 34.

As the current values used for each measurement of the Hct value and the second response current value, the current value at the end point of application of the DC voltage (second voltage) for measuring the Hct value and the DC voltage for measuring the Hct value (DC voltage for measuring the Hct value). Either the current value at a predetermined time point during application of the second voltage) may be acquired.

The control unit 23 calculates the ratio of the first response current value and the second response current value obtained by the measurement unit 35, and corresponds to this ratio with the second response current value (may be the first response current value). Calculate the value indicating the relationship. The storage unit 24 stores in advance data (temperature calibration curve table) showing the relationship between the above-mentioned ratio and the second response current value and the temperature of the sample in the flow path 9. The control unit 23 measures the temperature of the corresponding sample using the temperature calibration curve table. In the measuring device (glucose meter 20) according to the present embodiment, with respect to the GLU response current value measured by the GLU measuring unit 33 and the Hct response current value measured by the Hct measuring unit 34. Perform temperature correction. Therefore, as will be described later, the storage unit 24 also includes a temperature-corrected calibration curve table for glucose values and a temperature-corrected calibration curve table for Hct response current values.

Further, the storage unit 24 stores calibration curve data (GLU calibration curve data) that converts the GLU response current value measured by the GLU measurement unit 33 into a glucose value. The control unit 23 calculates the glucose value by converting the GLU response current value into the glucose value using the GLU calibration curve data. The glucose value is stored in the storage unit 24 or output (displayed or the like) from the output unit 25. The GLU calibration curve data may be a calibration curve table (GLU calibration curve table).

The control unit 23 further corrects the glucose value and the Hct response current value by using the information indicating the temperature of the sample. The storage unit 24 stores the temperature-corrected calibration curve table for glucose value and the temperature-corrected calibration curve table for Hct response current value, and the control unit 23 corrects the temperature of the glucose value using the temperature-corrected calibration curve table for glucose value. .. Further, the control unit 23 can perform temperature correction of the Hct response current value by using the temperature correction calibration curve table for the Hct value.

The control unit 23 corrects the glucose value by using the Hct response current value temperature-corrected by the Hct value temperature-corrected calibration curve table with respect to the glucose value temperature-corrected by the glucose value temperature-corrected calibration curve table. I do. The storage unit 24 has a calibration curve table (Hct correction table) for hematocrit-correcting the glucose value temperature-corrected by the temperature-corrected calibration curve table for current values based on the Hct response current value temperature-corrected by the temperature-corrected calibration curve table for Hct values. ) Is remembered. The control unit 23 calculates the glucose value (final glucose value) obtained by finally temperature-correcting and hematocrit-correcting the temperature-corrected glucose value using the Hct correction table. The final glucose value is stored in the storage unit 24 or output from the output unit 25. In this way, the measurement accuracy of the glucose level can be improved.

The above method is an example, and the control unit 23 relatively indicates the acquired GLU response current value, Hct response current value, and the relationship between the first response current value and the second response current value (relative). Value: Ratio (quotient) or difference) and the correspondence between the first response current value and the second response current value are calculated. The control unit 23 can calculate the temperature-corrected glucose value, the temperature-corrected Hct value, or the final glucose value by using the temperature information of the sample obtained based on the correspondence. Specifically, the control unit 23 may correct the glucose value instead of the GLU response current value, or may correct the Hct value instead of the Hct response current value, using the information indicating the temperature of the sample. In addition, instead of performing temperature correction for the glucose value (GLU response current value) and Hct value (Hct response current value) using the respective calibration curve tables, hematocrit correction is performed as follows. You may. That is, hematocrit correction is first performed based on the glucose value (GLU response current value) and the hematocrit value (Hct response current value). Then, the final glucose value is calculated using the hematocrit-corrected glucose value and the information indicating the temperature of the sample. In such an embodiment, the storage unit 24 may store the calibration curve data or the calibration curve table, the control unit 23 may appropriately use the calibration curve data or the calibration curve table, and the output unit 25 may also appropriately output the calibration curve data. Can be done.

Although not shown, when the biosensor 10 has the three-electrode configuration (configuration of the biosensor 10A) shown in FIG. 2 or the above-mentioned 5 to 8 electrode configuration, the blood glucose level is a connector that matches the electrode configuration. A total of 20 can have. Further, the control unit 23 controls the switch 31 so that the glucose meter 20 can measure the first and second response current values, the Hct response current value, and the GLU response current value using appropriate electrodes, and the blood glucose level. The electrical connection relationship between the total of 20 and each electrode can be changed.

As an example, it is assumed that the biosensor 10A having the three-electrode configuration shown in FIG. 2 is used. In this assumption, the control unit 23 controls the SW31 at the time of measuring the glucose level, and the working electrode (electrode 17) and the counter electrode (electrode 16) for measuring the glucose level are electrically connected to the blood glucose meter 20. The electrode 15 is in a cut state. That is, the GLU measuring unit 3
3 applies a DC voltage for glucose measurement from the electrode 17 to the electrode 16 according to an instruction from the control unit 23, and measures the GLU response current value with respect to this DC voltage.

The control unit 23 controls the SW31 at the time of measuring the Hct value so that the working electrode (electrode 15) and the counter electrode (electrode 16) for measuring the Hct value are electrically connected to the blood glucose meter 20. The electrode 17 is cut. The Hct measuring unit 34 performs the following operations. That is, the Hct measuring unit 34 applies a DC voltage for measuring the Hct value between the electrode 15 and the electrode 16, and after the application is started and the application is continuous for a predetermined time, the Hct response current value corresponding to the Hct value is obtained. Measure.

When the electrode 16 and the electrode 17 are connected by the SW31 and the electrode 15 is disconnected, the measuring unit 35 applies a DC voltage (first voltage) from the electrode 17 to obtain a first response current value. It is continuously applied for a predetermined time in the direction toward 16. The measuring unit 35 measures, for example, the response current value at the end point of a predetermined time as the first response current value. However, instead of acquiring the current value at the end point of the first voltage as the first response current value, the current value at a predetermined timing during application of the first voltage may be acquired as the first response current value. It should be noted that this step may be common to the measurement of the Hct response current value, or may be partially common to the measurement of the Hct response current value, as in the 4-electrode configuration. Further, the electrode 17 and the electrode 15 can also be used to obtain the first response current value. In this case, the measuring unit 35 has a DC voltage (first voltage) for obtaining the first response current value when the electrode 16 is disconnected by the SW31 and the electrode 17 and the electrode 15 are connected. Is continuously applied from the electrode 17 to the electrode 15 for a predetermined time, and for example, the response current value at the end point of the predetermined time is measured as the first response current value. However, although the first response current value is acquired by the current value at the end point of the first voltage, the current value at a predetermined time point during application of the first voltage may be acquired.

Further, when measuring the second response current value, the control unit 23 controls the SW31 so that, for example, the electrode 15 and the electrode 16 are electrically connected to the glucose meter 20, and the electrode 17 is disconnected. To. The Hct measuring unit 34 applies a DC voltage (second voltage) for measuring the second response current value between the electrode 15 and the electrode 16 according to the instruction from the control unit 23. The Hct measuring unit 34 measures the response current value with respect to this DC voltage as the second response current value after the application is started and the application is continuous for a predetermined time.

As described above, in the blood glucose meter 20 according to the embodiment, the Hct measuring unit 34 and the electrodes 15 and 16 used for measuring the Hct value can be used for measuring the second response current value. Therefore, the step of measuring the Hct response current value and the step of measuring the second response current value can be shared. That is, the Hct response current value may be measured as the second response current value. In this case, the voltage for measuring the Hct value becomes the second voltage for measuring the second response current value. Further, as in the 4-electrode configuration, a part of the step of measuring the Hct response current value is common to the step of measuring the second response current value, and the step of measuring the Hct value using the Hct measuring unit 34. A configuration may be adopted in which the step of measuring the second response current value and the step are performed separately.

As the current values used for each measurement of the Hct value and the second response current value, the current value at the end point of application of the DC voltage (second voltage) for measuring the Hct value and the DC voltage for measuring the Hct value (DC voltage for measuring the Hct value). Either the current value at a predetermined time point during application of the second voltage) may be acquired.

By adopting the above configuration, the temperature of the sample can be measured and the glucose value can be further corrected in the same manner as in the 4-electrode configuration. The measurement unit 35 corresponds to the first measurement unit, the Hct measurement unit 34 corresponds to the second measurement unit, and the control unit 23 corresponds to the calculation unit. The second response current value may be measured by the Hct measuring unit 34 at a timing different from the Hct response current value, or may be measured by a measuring unit other than the Hct measuring unit 34.

<Operation example>
FIG. 4 is a flowchart showing an operation example of the blood glucose meter 20 using the biosensor 10 having four electrodes. In S01 shown in FIG. 4, the sample is spotted. That is, when the biosensor 10 is connected to the blood glucose meter 20 and the opening 9a of the other end 10b of the biosensor 10 is brought into contact (dotted) with the blood (biological sample) collected from the subject, due to the capillary force. Blood is drawn into the flow path 9 and fills the flow path 9 and moves toward the air hole 7.

The control unit 23 applies the voltage to the electrode before the spotting, observes the applied voltage, detects the change in the voltage due to the contact between the blood and the electrode due to the spotting, and the blood flows into the flow path 9. Detect that it has been introduced. Then, the control unit 23 starts measuring the Hct value (S02).

In S02, the control unit 23 controls the Hct measurement unit 34, and applies a DC voltage (second voltage) for obtaining an Hct value and a second response current value to the blood using the electrodes 11 and 12. .. That is, the control unit 23 issues an instruction to the Hct measurement unit 34 to apply a DC voltage (for example, 4V) corresponding to the second voltage to the electrodes 11 and 12.

The Hct measuring unit 34 continuously applies the DC voltage corresponding to the second voltage for a predetermined time (about 2.5 seconds: corresponding to the second time), waits for the predetermined time to elapse, and waits for the predetermined time. The response current value (Hct response current value and the second response current value) of the blood at the elapsed time (end point of the predetermined time) is measured (S03). The Hct measuring unit 34 A / D converts the Hct response current value and the second response current value and sends them to the control unit 23.

When the control unit 23 acquires the Hct response current value and the second response current value, the control unit 23 starts measuring the glucose value. That is, the control unit 23 applies a voltage (for example, 0.2 V) for measuring the glucose value to blood (S04). That is, the control unit 23 instructs the GLU measurement unit 33 to apply a DC voltage to the blood in the flow path 9 using the electrode pair (electrode 13 and electrode 14) for measuring the glucose level. The GLU measuring unit 33 applies a DC voltage according to the instruction. The GLU measuring unit 33 measures the GLU response current value of blood with respect to the voltage (S05). The GLU measurement unit 33 A / D-converts the GLU response current value and transmits it to the control unit 23.

Next, the control unit 23 gives an instruction to the measurement unit 35, and the measurement unit 35 uses the electrode pair (for example, the electrode 13 and the electrode 12) used for measuring the first response current value in the flow path 9. A DC voltage (2.5 V) corresponding to the first voltage is applied to the blood (S06). At this time, a voltage is applied from the electrode 13 provided with the reagent 8 to the electrode 12 not provided with the reagent 8. The measuring unit 35 continuously applies the DC voltage corresponding to the first voltage for a predetermined time (about 2.5 seconds: corresponding to the first time), and sets the response current value at the end point of the predetermined time as the first response. It is measured as a current value, A / D converted, and sent to the control unit 23 (S07).

In S08, the control unit 23 operates as a calculation unit to calculate the blood temperature. That is, the ratio between the first response current value and the second response current value is calculated, a value indicating the correspondence between this ratio and the second response current value is calculated, and this value and the temperature calibration curve data are used. And measure the temperature of the blood.

In S09, the control unit 23 calculates the glucose value in blood using the GLU response current value acquired in S05 and the GLU calibration curve data, and further, the blood temperature calculated in S08 and the glucose value temperature. The glucose level is temperature-corrected using a corrected calibration curve table. Further, the control unit 23 corrects the blood temperature calculated in S08 and the Hct response current value (corresponding to the Hct value) obtained in S03 using the temperature-corrected calibration curve table for the Hct response current value. Then, the corrected glucose value is hematocrit-corrected using the corrected Hct response current value, and the final glucose value is obtained.

The control unit 23 outputs the final glucose value (S10). That is, the control unit 23 stores the final glucose value acquired in S09 in the storage unit 24 and displays it in the output unit 25. The control unit 23 can also use the output unit 25 to transmit the final glucose value to another device via a wired or wireless network.

In the operation example shown in FIG. 4, the Hct value is measured before the glucose value is measured, but the reverse may be performed. Further, although the measurement of the second response current value is performed before the measurement of the first response current value, the reverse may be performed. Further, the measurement of the response current corresponding to the glucose value is performed before the measurement of the first and second response current values and between the measurement of the first response current value and the measurement of the second response current value. 2 It may be after the measurement of the response current value.

[Example 1]
[Example 1-1]
As Example 1-1, the following experiments were performed. In Example 1-1, as the biosensor, a biosensor having a configuration of a biosensor 10A having three electrodes shown in FIG. 2 and having electrodes 15 to 17 made of ruthenium was produced. Reagent 8 was provided on the electrode 17. The prescription and manufacturing method of the reagent 8 are as follows. Polyvinyl alcohol (PVA146,000) 0.8% by weight, ruthenium compound [Ru (NH ₃ ) ₆ ] Cl ₃ , 1.6% by weight, FAD-GDH 2.7U,
An enzyme solution containing 0.3% by weight of 1-methoxy PES and ACES buffer (pH 6.5) was prepared. Reagent 8 was obtained by dispensing 0.5 μL of this enzyme solution and drying at 25 ° C.

As a biological sample, a mixture of whole blood (blood) of two people was used. As a sample, a sample having a constant glucose value and having an Hct value adjusted to 20%, 42%, and 70% was prepared. Further, as a sample, a sample whose temperature was adjusted to 8 ° C., 25 ° C., and 40 ° C. was prepared.

The measurement of the first and second response current values, the measurement of the Hct response current value (measurement of the Hct value) and the measurement of the GLU response current value (measurement of the glucose value) for each sample were performed under the following conditions.
(1) Measurement of First Electrical Response Value After connecting the electrodes (electrodes 16 and 17) for measuring the first response current value of the biosensor 10A into which the sample is introduced into the flow path 9 to the blood glucose meter 20. After 0.5 seconds (0.5 second open circuit), the application of the DC voltage (2.5 V: corresponding to the first voltage) for measuring the first response current value from the electrode 17 to the electrode 16 was started. .. The application of the DC voltage was continued for 2.5 seconds, and the response current value (first response current value) 2.5 seconds after the start of application (3 seconds after the start of measurement) was measured.

(2) Measurement of the second response current value and the Hct response current value The application was stopped 2.5 seconds after the start of the application of DC2.5V, and the circuit was opened (non-energized state) for 3 seconds. During this period, the electrodes for measuring the second response current value of the biosensor 10A (electrodes 15 and 16) are connected to the blood glucose meter 20, and the DC voltage for measuring the second response current value (4.0 V: second). (Corresponding to voltage) was applied between the electrode 15 and the electrode 16. The application was continuously performed for 2.5 seconds, and the response current value (second response current value) at 7.5 seconds from the start of measurement, which was 1.5 seconds after the application of the second voltage, was measured. ..

(3) Measurement of glucose value The application was stopped 1.5 seconds after the start of application of DC 4.0 V (second voltage), and the circuit was opened (non-energized state) for 5 seconds. During this period, the glucose value measuring electrodes (electrodes 16 and 17) of the biosensor 10A were connected to the blood glucose meter 20, and a DC voltage (0.2V) for measuring the glucose level was continuously applied for 7 seconds. .. In this way, the Hct value and the glucose value were continuously measured for the same sample.

[Comparative Example 1]
As Comparative Example 1, in the step of applying a DC voltage for obtaining the first response current value (referred to as step (1)), as an electrode pair to which a DC voltage is applied, an electrode (electrode 15 and an electrode) to which the reagent 8 is not provided is provided. 16) was used. Other than that, the same experiment as in Example 1-1 was performed.

[Example 1-2]
As the second embodiment, in the step of applying the DC voltage for obtaining the second response current value (referred to as step (2)), DC 2.5V was applied as the second voltage. Other than that, the same experiment as in Example 1-1 was performed.

[Example 1-3]
As the third embodiment, in the step of applying the DC voltage for obtaining the second response current value (step (2)), DC 2.0V was applied as the second voltage. Other than that, the same experiment as in Example 1-1 was performed.

5 (A) to 5 (D) show the measurement results in Example 1-1. FIG. 5A shows a time course (change with the passage of time) when the temperature of the sample is 8 ° C., and FIG. 5B shows a time course when the temperature of the sample is 25 ° C. FIG. 5C shows a time course when the temperature of the sample is 40 ° C.

The Y-axis (vertical axis) of each graph of FIGS. 5 (A) to 5 (D) indicates the response current value (μA), and the X-axis (horizontal axis) indicates the time (seconds (sec)). Graphs G11 in FIGS. 5A to 5D show a response current (also referred to as a response signal) obtained by applying a first voltage to each of a plurality of samples having an Hct value of 20%. Further, the graph G12 shows the response current obtained by applying the first voltage to each of a plurality of samples having an Hct value of 42%. Further, the graph G13 shows the response current obtained by applying the first voltage to each of a plurality of samples having an Hct value of 70%. Further, the graph G21 shows a response current obtained by applying a second voltage to each of a plurality of samples having an Hct value of 20%. Further, the graph G22 shows the response current obtained by applying a second voltage to each of a plurality of samples having an Hct value of 42%. Further, the graph G23 shows the response current obtained by applying a second voltage to each of a plurality of samples having an Hct value of 70%.

FIG. 5D shows a first response current value and a second response current value for each sample, which are examples of values that relatively show the relationship between the first response current value and the second response current value for each sample. A value indicating the relationship between the 3-second value / 7.5-second value (first response current value / second response current value), which is a relative value (ratio) with, and the second response current value, which is a 7.5-second value. It is a graph marked with a point indicating. The Y-axis (vertical axis) of the graph of FIG. 5 (D) is the first response current value / the second response current value, and the X-axis (horizontal axis) is the second response current value (μA). The triangular mark (point) indicates the correspondence relationship for each sample whose temperature of the sample is adjusted to 40 ° C. Further, the quadrangular points in which the vertices are arranged in the X-axis direction and the Y-axis direction of the graph indicate the correspondence relationship for each sample in which the temperature of the sample is adjusted to 25 ° C. Further, the quadrangular points whose sides are arranged in the X-axis direction or the Y-axis direction indicate the correspondence relationship of each sample whose temperature of the sample is adjusted to 8 ° C. The points corresponding to each temperature in FIG. 5 (D) are distributed in the left region, the right region, and the region between them (referred to as an intermediate region) in the graph, and the points in the left region are distributed. The points in the intermediate region are the points when the Hct value is 42%, and the points in the right region are the points when the Hct value is 70%. be.

6 (A) to 6 (D) show the measurement results in Comparative Example 1. FIG. 6A shows a time course when the temperature of the sample is 8 ° C., and FIG. 6B shows a time course when the temperature of the sample is 25 ° C. FIG. 6C shows a time course when the temperature of the sample is 40 ° C. FIG. 6D shows a 3-second value / 7.5-second value (first response current value), which is an example of a value that relatively shows the relationship between the first response current value and the second response current value for each sample. / It is the graph which marked the point which shows the value which shows the correspondence | corresponding relationship between the 2nd response current value) and the 2nd response current value which is a 7.5 second value. Since the explanation of the graphs shown in FIGS. 6A to 6D is the same as the explanation given for the graphs shown in FIGS. 5A to 5D, the description thereof will be omitted again.

7 (A) to 7 (D) show the measurement results in Example 1-2. FIG. 7A shows a time course when the temperature of the sample is 8 ° C., and FIG. 7B shows a time course when the temperature of the sample is 25 ° C. FIG. 7C shows a time course when the temperature of the sample is 40 ° C. FIG. 7D shows a 3-second value / 7.5-second value (first response current value), which is an example of a value that relatively shows the relationship between the first response current value and the second response current value for each sample. / It is a graph which marked the value which shows the correspondence relationship between the 2nd response current value) and the 2nd response current value which is a 7.5 second value. Since the explanation of the graphs shown in FIGS. 7A to 7D is the same as the explanation given for the graphs shown in FIGS. 5A to 5D, the description thereof will be omitted again.

8 (A) to 8 (E) show the measurement results in Examples 1-3. FIG. 8A shows a time course when the temperature of the sample is 8 ° C., and FIG. 8B shows a time course when the temperature of the sample is 25 ° C. FIG. 8C shows a time course when the temperature of the sample is 40 ° C. FIG. 8D is an enlarged view showing the response signals (graphs G21, G22, G23) by changing the scale of the X-axis in FIG. 8B for 6 to 10 seconds. FIG. 8E shows a 3-second value / 7.5-second value (first response current value), which is an example of a value that relatively shows the relationship between the first response current value and the second response current value for each sample. / It is the graph which marked the point which shows the value which shows the correspondence | corresponding relationship between the 2nd response current value) and the 2nd response current value which is a 7.5 second value. Since the explanation of the graphs shown in FIGS. 8A to 8E is the same as the explanation given for the graphs shown in FIGS. 5A to 5D, the description thereof will be omitted again.

Referring to FIGS. 5 (D), 7 (D), and 8 (E), in Examples 1-1, 1-2, and 1-3, the points corresponding to the same Hct value are the same regions. The regions of the graph can be divided into three regions corresponding to Hct 20%, 42%, and 70%, respectively, so that the regions do not overlap with each other. In each of the divided regions, the lower the temperature, the lower the position of the point indicating the correspondence. That is, there is a correlation between the correspondence relationship and the temperature. From these, the resolution applicable to temperature measurement is obtained. On the other hand, in Comparative Example 1 (see FIG. 6D), points where the temperatures are different from each other cannot be divided into different regions without overlapping the regions. This means that the resolution available for temperature measurement is not available. From this, the first response current value by applying a voltage from the working electrode provided with the reagent to the counter electrode and the second response current value by applying the voltage to the two electrodes not provided with the reagent obtain the desired resolution. It turns out that it is necessary.

Further, in Example 1-1, the second voltage (4V) is higher than the first voltage (2.5V), and in Example 1-2, the second voltage (2.5V) is the second. It is an example that is the same as the voltage of 1 (2.5V), and Example 1-3 is an example in which the second voltage (2V) is lower than the first voltage (2.5V). From the results of FIGS. 5 (D), 7 (D), and 8 (E), the resolution of the correspondence shown in FIGS. 5 (D) and 8 (E) is higher than the resolution of the correspondence shown in FIG. 7 (D). Since it shows higher resolution, it can be seen that better resolution can be obtained when the second voltage is different from the first voltage (higher or lower) than when the second voltage is the same as the first voltage. In Example 1-3, referring to the graph of FIG. 8 (D), although the difference between the second response current values is smaller than that of Example 1-2 in the time course, it is carried out by using the correspondence. It can be seen that an appropriate resolution is obtained from Example 1-2.

The measured temperature is used in all of Examples 1-1, 1-2 and 1-3 to correct the measured Hct response current value (Hct value) and GLU response current value (glucose value). Therefore, the glucose value in each sample could be accurately measured as the final glucose value (not shown).

In each of Examples 1-1, 1-2, and 1-3, the DC voltage for measuring the second response current value was continuously applied for 2.5 seconds, and the second voltage was applied. The second response current value was measured 1.5 seconds after the application, but even if the DC voltage was applied for 1.5 seconds and the second response current value was measured at the end point of 1.5 seconds. good. In this way, the application time of the first voltage and the second voltage, and the predetermined time points for acquiring the first response current value and the second response current value can be appropriately changed. As the first response current value and the second response current value, the optimum values may be selected so as to have a correspondence relationship in which the optimum resolution can be obtained according to the characteristics of the analysis tool including the type of the reagent and the electrode used.

[Example 2]
[Example 2-1]
As Example 2-1 the following experiment was carried out. Using the biosensor 10A used in Example 1, 0.5 seconds after introducing the sample prepared in the same manner as in Example 1 into the flow path 9, the electrode 17 (with reagent 8) to the electrode 16 (reagent 8) were introduced. A DC voltage (2.5 V) toward (none) was continuously applied for 2.5 seconds. The response current value (corresponding to the first response current value) after 2.5 seconds had elapsed was acquired. This is used as the response current value in the first measurement. Then, after the open circuit (non-energized state) for 3 seconds, a DC voltage (2.5 V) was continuously applied between the electrode 15 (without reagent) and the electrode 16 (without reagent) for 2.5 seconds. The response current value (corresponding to the second response current value) at 1.5 seconds was acquired. This is used as the response current value in the second measurement. Such an experiment was performed on each sample having a constant glucose level, Hct values of 70%, 42%, and 20%, respectively, and the temperature was adjusted to 40 ° C., 10 ° C., and 27 ° C.

Table 1 below shows the results of the experiment according to Example 2-1. The Hct value (%) in Table 1 indicates the Hct value of the sample having a temperature of 40 ° C., 10 ° C., and 27 ° C., respectively. The response current value (μA) indicates the response current value in the second measurement described above. The response current value ratio is the ratio of the response current value in the first measurement to the response current value in the second measurement, and the ratio is the response current value in the first measurement and the response current value in the second measurement. This is an example of a value that relatively indicates the relationship between. FIG. 9 shows the response current value ratio shown in Table 1 ([response current value in the first measurement] / [2].
The graph which marked the point which shows the correspondence relation between [response current value in the second measurement]) and [response current value in the second measurement] is shown.

The Y-axis (vertical axis) of the graph of FIG. 9 is the response current value ratio, and the X-axis (horizontal axis) is the response current value (μA). The triangular dots indicate the correspondence for each sample whose sample temperature has been adjusted to 40 ° C. Further, the quadrangular points in which the vertices are arranged in the X-axis direction and the Y-axis direction of the graph indicate the correspondence relationship for each sample in which the temperature of the sample is adjusted to 25 ° C. Further, the quadrangular points whose sides are arranged in the X-axis direction or the Y-axis direction indicate the correspondence relationship of each sample whose temperature of the sample is adjusted to 8 ° C. Further, in FIG. 9, points corresponding to each temperature are placed in a region on the left side of the graph, a region on the right side, and a region (intermediate region) between them. The points in the left area are for samples with an Hct value of 70%. The middle point is for a sample having an Hct value of 42%. The points on the right side are for samples with an Hct value of 20%.

Regarding the points shown in the graph of FIG. 9, the points corresponding to the same Hct value belong to the same region, and the regions of the graph correspond to Hct 20%, 42%, and 70%, respectively, so that the regions do not overlap. It can be divided into areas. Further, the points belonging to each region show a relationship that the position of the point becomes lower as the temperature becomes lower even if the Hct value is the same. From these, it can be seen that according to Example 2-1 the resolution suitable for temperature measurement can be obtained as in Examples 1-1, 1-2, and 1-3.

[Example 2-2]
As Example 2-2, the following experiment was performed. Using the biosensor 10A used in Example 1, 0.5 seconds after introducing the sample into the flow path 9, a DC voltage (2.) was established between the electrode 15 (without reagent) and the electrode 17 (without reagent). 5V) was continuously applied for 2.5 seconds. The response current value (corresponding to the second response current value) after 2.5 seconds had elapsed was acquired. This is used as the response current value in the first measurement. Then, after an open circuit (non-energized state) for 3 seconds, a DC voltage (2.5 V) from the electrode 17 (with reagent 8) to the electrode 16 (without reagent 8) was continuously applied for 2.5 seconds. The response current value (corresponding to the first response current value) at 1.5 seconds was acquired. This is used as the response current value in the second measurement. Such an experiment was performed on each sample having a constant glucose level, Hct values of 70%, 42%, and 20%, respectively, and the temperature was adjusted to 40 ° C., 10 ° C., and 27 ° C.

Table 2 below shows the results of the experiment according to Example 2-2. Since the explanation of the Hct value (%), the response current value (μA), and the response current value ratio in Table 2 is the same as the explanation given for Table 1, the explanation will be omitted again. FIG. 10 marks the correspondence between the response current ratio in Table 2 ([response current value in the first measurement] / [response current value in the second measurement]) and [response current value in the second measurement]. The graph is shown.

Since the explanation of the graph shown in FIG. 10 is the same as the explanation given for the graph shown in FIG. 9, the description again will be omitted. As shown in FIG. 10, it can be seen that the same findings as those obtained in Example 2-1 can be obtained in Example 2-2 as well, and that the resolution suitable for temperature measurement is obtained. Further, from the results of Examples 2-1 and 2-2, it can be seen that the step of obtaining the first response current value and the step of obtaining the second response current value may be reversed.

[Comparative Example 2-1]
As Comparative Example 2-1 the following experiment was performed. Using the biosensor 10A used in Example 1, 0.5 seconds after introducing the sample into the flow path 9, the DC voltage (2.) from the electrode 17 (with the reagent 8) to the electrode 16 (without the reagent 8). 5V) was continuously applied for 2.5 seconds. The response current value after 2.5 seconds passed was acquired. This is used as the response current value in the first measurement. Then, after an open circuit (non-energized state) for 3 seconds, a DC voltage (2.5 V) from the same electrode 17 (with reagents) to electrode 16 (without reagents) is continuously applied for 2.5 seconds. Then, the response current value at 1.5 seconds was obtained. This is used as the response current value in the second measurement. Such an experiment was performed on each sample having a constant glucose level, Hct values of 70%, 42%, and 20%, respectively, and the temperature was adjusted to 40 ° C., 10 ° C., and 27 ° C.

Table 3 below shows the results of the experiment according to Comparative Example 2-1. Since the explanation of the Hct value (%), the response current value (μA), and the response current value ratio in Table 3 is the same as the explanation given for Table 1, the explanation will be omitted again. FIG. 11 shows the correspondence between the response current ratio in Table 3 ([response current value in the first measurement] / [response current value in the second measurement]) and [response current value in the second measurement]. Shows a graph with dots marked.

Since the explanation of the graph shown in FIG. 11 is the same as the explanation given for the graph shown in FIG. 9, the description again will be omitted. From the graph of FIG. 11, when an electrode provided with a reagent is used as an electrode for obtaining two response current values (when both of the two response current values are response current values corresponding to the first response current value). ), The following findings can be obtained. That is, unlike Examples 2-1 (FIG. 9) and Example 2-2 (FIG. 10), the points corresponding to each Hct value cannot be divided into three non-overlapping regions, which is suitable for temperature measurement. It turns out that the resolution cannot be obtained.

[Comparative Example 2-2]
As Comparative Example 2-2, the following experiment was performed. Using the biosensor 10A used in Example 1, 0.5 seconds after introducing the sample into the flow path 9, a DC voltage (2.) was established between the electrode 15 (without reagent) and the electrode 17 (without reagent). 5V) was continuously applied for 2.5 seconds. The response current value after 2.5 seconds passed was acquired. This is used as the response current value in the first measurement. Then, after an open circuit (non-energized state) for 3 seconds, a DC voltage (2.5 V) is continuously applied between the electrodes 15 (without reagents) and electrodes 17 (without reagents), which are the same electrodes, for 2.5 seconds. And the response current value at 1.5 seconds was obtained. This is used as the response current value in the second measurement. Such an experiment was performed on each sample having a constant glucose level, Hct values of 70%, 42%, and 20%, respectively, and the temperature was adjusted to 40 ° C., 10 ° C., and 27 ° C.

Table 4 below shows the results of the experiment according to Comparative Example 2-2. Since the explanation of the Hct value (%), the response current value (μA), and the response current value ratio in Table 4 is the same as the explanation given for Table 1, the explanation will be omitted again. FIG. 12 shows the correspondence between the response current ratio in Table 4 ([response current value in the first measurement] / [response current value in the second measurement]) and [response current value in the second measurement]. A graph with dots marked is shown in FIG.

Since the explanation of the graph shown in FIG. 12 is the same as the explanation given for the graph shown in FIG. 9, the description again will be omitted. From the graph of FIG. 12, when an electrode without a reagent is used as an electrode for obtaining two response current values (when both of the two response current values are response current values corresponding to the second response current value). ), The following findings can be obtained. That is, unlike Examples 2-1 (FIG. 9) and Example 2-2 (FIG. 10), the points corresponding to each Hct value cannot be divided into three non-overlapping regions, which is suitable for temperature measurement. It turns out that the resolution cannot be obtained.

From the results of Example 2-1 and Example 2-2, Comparative Example 2-1 and Comparative Example 2-2, in order to obtain an appropriate resolution (different correlation at each temperature) that can be used for temperature measurement. The response current value of the sample to the voltage applied from the electrode provided with the reagent using two electrodes including the electrode provided with the reagent, and the response current value of the sample to the voltage applied from the electrode provided with the reagent and applied from either electrode using the two electrodes not provided with the reagent. It was found that the response current value of the sample to the voltage was required. On the other hand, it was found that sufficient results could not be obtained for either response current value when two electrodes including an electrode provided with a reagent were used or when two electrodes not provided with a reagent were used. rice field. On the other hand, from the results of Examples 2-1 and 2-2, it was found that the step of obtaining the first response current value and the step of obtaining the second response current value may be reversed.

The lower limit of the applied voltage to the electrodes is about 1.0 V DC in view of the voltage at which electrolysis of water occurs. Further, if it is 1.0 V or more, the response current value is not affected by the component to be measured in the sample. On the other hand, since bubbles are generated in the sample as the applied voltage rises, the response current value becomes a value affected by the bubbles, so that the upper limit of the applied voltage is about 7 V at which no bubbles are generated. For example, in the case of the above-mentioned embodiment using a ruthenium electrode or the like, it is preferable that the lower limit is 1.5 V and the upper limit is 5.0 V, and in the case of the first voltage, the lower limit is 2. At 0 V, the upper limit is more preferably 3.5 V, and in the case of the second voltage, the lower limit is 2.0 V and the upper limit is more preferably 4.5 V. It should be noted that this is the case of the ruthenium electrode, and when different electrodes are used, the appropriate applied voltage is in a different range. Further, the appropriate applied voltage may be in a different range depending on the type of salt. However, in the case of an electrode or salt used in a general analytical tool, it is preferable that the applied voltage is selected from 1 V or more and 7 V or less. Further, as the voltage, a voltage whose direction does not change with time, that is, a DC (direct current) voltage is selected.

According to the measurement method and apparatus described in the embodiment, the temperature of the sample can be appropriately measured by using the electrodes provided in the analytical tool, and the correction amount applied to the temperature correction of the Hct value and the glucose value can be optimized. Can be planned. The configurations described in the above-described embodiments can be combined as appropriate.

8 ... Reagent 9 ... Channel 10 ... Biosensors 11-14, 15-17 ... Electrodes 20 ... Measuring device 33 ... Glucose measuring unit 34 ... Hematocrit measuring unit 35.・ ・ Measurement unit

Claims (12)

In a measuring method for measuring the temperature of a sample using an analytical tool including a reagent that reacts with a biological sample, a plurality of electrodes, and the flow path of the sample in which the reagent and the plurality of electrodes are arranged. ,
A step of applying a first voltage from an electrode provided with the reagent to the sample in the flow path using two electrodes selected from the plurality of electrodes including the electrode provided with the reagent. ,
The step of measuring the first response current value of the sample with respect to the first voltage, and
A step of applying a second voltage to the sample in the flow path using two electrodes selected from the plurality of electrodes and not provided with the reagent.
The step of measuring the second response current value of the sample with respect to the second voltage, and
The sample is based on the correspondence between the value indicating the relative relationship between the first response current value and the second response current value and either the first response current value or the second response current value. And the process of finding the temperature of
Measurement method including. The electrode different from the electrode provided with the reagent among the two electrodes to which the first voltage is applied is one of the two electrodes not provided with the reagent to which the second voltage is applied. The measuring method according to claim 1. The value that relatively indicates the relationship between the first response current value and the second response current value is the ratio of the first response current value to the second response current value, according to claim 1 or 2. Measuring method. The measuring method according to any one of claims 1 to 3, wherein the value of the first voltage and the value of the second voltage are different. The measuring method according to claim 4, wherein the value of the second voltage is larger than the value of the first voltage. The sample is blood
The measuring method according to any one of claims 1 to 5, wherein the second response current value is used as a value indicating the hematocrit value of the blood. The sample is blood
A voltage is applied from the electrode provided with the reagent among the two electrodes to which the first voltage is applied toward one of the two electrodes to which the second voltage is applied, and the voltage is applied to the blood. The measuring method according to any one of claims 1 to 6, further comprising a step of measuring a response current value corresponding to a glucose value. After the measurement of the second response current value, the response current value corresponding to the glucose value was measured, and the response current value was measured.
The measuring method according to claim 7, wherein the first response current value is measured after the response current value corresponding to the glucose value is measured. The first response current value indicates a current value at a predetermined time point during the first time when the first voltage is continuously applied for the first time.
The second response current value is according to any one of claims 1 to 8, which indicates a current value at a predetermined time point during the second time when the second voltage is continuously applied for the second time. Measurement method. A predetermined time point in the first time is the end point of the first time.
The measuring method according to claim 9, wherein a predetermined time point in the second time is an end point of the second time. The measuring method according to any one of claims 1 to 10, wherein the first voltage and the second voltage are 1 V or more and 7 V or less. In a measuring device for measuring the temperature of a sample using an analytical tool including a reagent that reacts with a biological sample, a plurality of electrodes, and the flow path of the sample in which the reagent and the plurality of electrodes are arranged. ,
Using two electrodes selected from the plurality of electrodes, including the electrode provided with the reagent, a first voltage is applied to the sample in the flow path from the electrode provided with the reagent, and the said. A first measuring unit for measuring the first response current value of the sample with respect to the first voltage, and
Using two electrodes selected from the plurality of electrodes and not provided with the reagent, a second voltage is applied to the sample in the flow path, and the second voltage of the sample is applied to the second voltage. The second measuring unit that measures the response current value,
The sample is based on the correspondence between the value indicating the relative relationship between the first response current value and the second response current value and either the first response current value or the second response current value. And the calculation unit that calculates the temperature of
Measuring equipment including.

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