KR101357134B1 - Method for Measuring Analytes in Blood Samples Using Electrochemical Biosensor and a Portable Analyzer - Google Patents

Abstract

A method for measuring the concentration of an analyte in a blood sample according to an embodiment of the present invention includes a cell containing a blood sample, and an electrochemical biosensor having a working electrode and an auxiliary electrode in the cell. Applying a constant voltage after the filling, applying a circulating voltage continuously after applying the constant voltage, and linearly combining a combination of at least two current values measured corresponding to the constant voltage and the circulating voltage. Obtaining the characteristic information of the; and correcting the influence of the characteristic information of the blood.
According to this structure, the accuracy of the biosensor can be improved by correcting the influence of hematocrit in the blood by applying a circulating voltage.

Description

Electrochemical biosensors, portable instruments, and methods for measuring the concentration of analytes in blood samples using them {Method for Measuring Analytes in Blood Samples Using Electrochemical Biosensor and a Portable Analyzer}

The present invention relates to an electrochemical biosensor, a portable measuring instrument and a method for measuring the concentration of analyte in a blood sample using the same, and more particularly, a portable meter for electrochemically analyzing a blood sample. An electrochemical biosensor, portable, which improves measurement accuracy by artificially correcting the effect of hematocrit on the measurement of the analyte concentration in the results obtained by the combination of chronoamperometry and cyclic voltammetry. It relates to a measuring instrument and a method for measuring the concentration of analyte in blood samples using the same.

Methods of measuring various metabolites or protein substances in the blood using electrochemical biosensors are known.

In particular, electrochemical biosensors are used as an essential tool for managing diabetes because they can measure blood glucose with portable instruments. For example, electrochemical biosensors, which are widely used in recent years, are configured to easily inhale a small amount of microliter blood sample into a capillary sample cell, so that blood sugar can be conveniently measured anywhere.

In spite of this convenience, electrochemical biosensors have a problem of inaccuracy due to various interferences (eg, ascorbic acid, uric acid, acetaminophen, etc.) that may exist in blood samples or the effect of different red blood cell volume (hematocrit) for each individual. have.

In order to solve this problem, many studies have been continued to minimize the effects of hematocrit by redesigning the structure of the biosensor or analyzing signals obtained from the biosensor.

U.S. Patent No. 5,708,247 discloses a biosensor that filters red blood cells using a fine mesh made of polyester. However, these biosensors require a large amount of blood for measurement and have a long measurement time.

US Patent No. 5,264,103 discloses a method of correcting the effects of hematocrit based on the time difference of electrical characteristics measured when blood enters each pair of electrodes using a biosensor having two pairs of electrodes on one plane. .

US Patent No. 7,258,769 discloses a method of correcting the effects of hematocrit by measuring the time that blood flows from a flow sensing electrode into a sample cell after a blood sample comes into contact with a large working electrode and an auxiliary electrode.

However, these methods have a problem that the accuracy of correction is lowered because the inflow time varies depending on the dry state of the biosensor reagent or the influence of external humidity.

US Patent Publication No. 2010-0276303, US Patent Publication No. 2010-0243476, and US Patent Publication No. 2007-0062822 are based on the fact that the amount of current generated when water is oxidized in a sample varies according to hematocrit. A method for correcting the effects of hematocrit has been disclosed.

This method requires a separate electrode to measure the amount of current generated when the water is oxidized, and the electrode must be made of precious metals such as palladium (Pd) or platinum (Pt). There is a problem that it is more expensive than the electrode.

In U.S. Patent No. 3,648,160, U.S. Patent 4,699,887, U.S. Patent 3,922,598, U.S. Patent 4,068,169, U.S. Patent 4,547,735, the higher the hematocrit, the lower the conductivity. In the US Patent 7,407,811, US Patent 7,390,667, US Patent 7,338,639 and the like to correct the effect of hematocrit, a method for measuring glucose is disclosed.

However, in this method, the electrical signal measured from the working electrode and the auxiliary electrode by applying the alternating voltage simultaneously contains the electrical signal due to glucose and the electrical signal related to the hematocrit in a complicated manner, and the hematocrit correction algorithm is complicated. There is also a problem that is not easy to secure reliability.

US Patent No. 6,287,451 discloses a method for correcting the effect of hematocrit by measuring the resistance of a sample using a biosensor having a separate resistance measurement electrode.

US Patent Publication No. 2011-0139634 discloses a method of calibrating hematocrit by measuring the conductivity of blood by applying alternating current to a biosensor having a separate, independent pair of electrodes. These methods measure hematocrit separately and are highly reliable, but the biosensor fabrication process can be complicated and the amount of sample required can be increased.

The present invention has been made to solve such a problem, and an object of the present invention is a portable meter that electrochemically analyzes blood samples without modifying existing biosensors. Electrochemical biosensors, portable instruments, and blood using them that improve the accuracy of measurement by artificial intelligence algorithms that compensate for the effects of hematocrit on the measurement of the analyte concentration in the results obtained by a combination of cyclic voltammetry. It is to provide a method for measuring the concentration of analyte in a sample.

Method for measuring the concentration of the analyte in the blood sample according to an embodiment of the present invention,

Applying a constant voltage after the blood sample is filled to the cell for the cell containing the blood sample, and the electrochemical biosensor having the working electrode and the auxiliary electrode in the cell; Obtaining the characteristic information of blood by linearly combining at least two current values measured corresponding to the predetermined voltage and the circulating voltage, and correcting the influence of the characteristic information of blood. Characterized in that it comprises a.

According to one embodiment of the invention, for a small amount of blood sample, it is possible to use the existing biosensor without incurring complicated manufacturing process or cost, and measured by applying a circulating voltage continuously after applying a constant voltage to the existing biosensor By combining the current values in a linear combination, it is possible to obtain the characteristic information in the blood, for example, hematocrit, without being complicated, thereby increasing the measurement accuracy of the concentration of analyte, such as a specific substance, especially glucose, in the blood sample.

In addition, according to one embodiment of the present invention, using a method for measuring the concentration of a specific substance in the blood according to an embodiment of the present invention for a small amount of blood sample, without using a complicated manufacturing process or costs for existing biosensors It can be used, and only the application of electric voltage and circulating voltage can provide a practical and economical portable instrument that can increase the accuracy of the measurement of the analyte, that is, the specific substance concentration in the blood sample.

1 is a conceptual block diagram of a portable instrument connected to a face-to-face biosensor according to an embodiment of the present invention.
2 is a conceptual block diagram of a portable instrument connected to a planar biosensor according to an embodiment of the present invention.
Figure 3 is a flow chart for explaining a method for measuring the concentration of a specific substance in the blood according to an embodiment of the present invention.
4 is a flowchart illustrating a blood glucose measurement method according to an embodiment of the present invention.
FIG. 5A is a graph illustrating a change in time-applied voltage (applied voltage vs. time) to explain a blood glucose measurement method according to a comparative example.
FIG. 5B is a graph showing a current value for the glucose standard sample at the end point of time applied voltage of FIG. 5A.
FIG. 6A is a graph illustrating the application of a cyclic voltage at the end point of time applied voltage of FIG. 5A.
FIG. 6B is a graph in which the time-dependent voltage is changed in FIG. 6A.
FIG. 6C is an enlarged view of the current value profile for the first cyclic voltage of FIG. 6A.
FIG. 6D is a graph illustrating a relationship between a current value and an applied voltage with respect to the second cyclic voltage of FIG. 6C.
7 is a graph showing a measurement error of the method for measuring the concentration of a specific substance in the blood according to an embodiment of the present invention.
8 is a graph showing a measurement error of the method for measuring the concentration of a specific substance in the blood according to another embodiment of the present invention.

Hereinafter, a method for measuring the concentration of a specific substance in blood and a portable measuring device using the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present specification, it is described as a preferred embodiment to correct the occurrence of a measurement error by the hematocrit at the time of blood glucose measurement, but as in the glucose test, various metabolites such as cholesterol, lactate, creatinine by introducing a specific enzyme Concentrations of organic or inorganic substances, such as hydrogen peroxide, alcohols, amino acids, and gurutamate, can also be corrected in the same way.

Therefore, the present invention can be used for quantification of various metabolites by varying the type of enzyme included in the sample layer composition.

For example, glucose oxidase (GOx), glucose dehydrogenase (GDH), glutamate oxidase glutamate dehydrogenase, cholesterol oxidase, cholesterol esterase, Lactate oxidase, ascorbic oxidase, alcohol oxidase, alcohol dehydrogenase, bilirubin oxidase and the like can be used to quantify glucose, glutamate, cholesterol, lactate, ascorbic acid, alcohol, bilirubin and the like. .

In a portable measuring device according to an embodiment of the present invention, a working electrode and an auxiliary electrode are provided to face each other on different planes, and a face type electrochemical coated with a reagent composition including an enzyme and an electron transfer medium according to a material on the working electrode. Biosensors can be applied.

In addition, the portable measuring instrument according to an embodiment of the present invention, the working electrode and the auxiliary electrode is provided on one plane, the planar electrochemical bio-coated with the reagent composition including the enzyme and the electron transfer medium according to the material on the working electrode Sensors can be applied.

First, a method for measuring the concentration of a specific substance in blood and a portable measuring device using the same will be described with reference to FIGS. 1 to 4.

1 and 2, the portable measuring device 100, 100 'according to an embodiment of the present invention is loaded with a face-to-face or planar electrochemical biosensor 110, 110', the electrochemical bio The constant voltage applying unit (120, 120 '), the cyclic voltage applying unit (130, 130'), and the constant voltage applying unit (120, 120 ') for applying a constant voltage to the sensor (110, 110') When a constant voltage is applied to the electrochemical biosensors 110 and 110 ', the current value and the cyclic voltage applying unit 130 according to the redox reaction of the enzyme and the electron transfer medium of the electrochemical biosensors 110 and 110' Correction processor 140, 140 'and the constant voltage applying unit 120, 120' and the circulating voltage applying unit for correcting the effect of the hematocrit by analyzing the current value by the circulating voltage applied by 130 and 130 ′, a controller 150 and 150 ′ that controls the correction processor 140 and 140 ′ and outputs a concentration of a specific substance, It characterized in that it comprises a 'display unit (160, 160 for displaying the output of) the control unit (150, 150).

Referring to FIG. 1, the biosensor 110 used in the portable measuring device 100 according to an exemplary embodiment of the present invention will be described in detail. The upper and lower plates may be formed of two flat insulating plates made of an insulating material such as synthetic resin, for example, polyester. The working electrode 103 and the auxiliary electrode 104 are formed by screen printing with carbon / graphite so as to face each of the auxiliary electrodes 101 and 102 separately, and the auxiliary electrode is provided on the lower plate 101 having the working electrode 103. An electrode connecting portion 105 connectable with the 104 is formed, and a part of the electrode connecting portion 105 has a circuit contact that is three-dimensionally connected to the auxiliary electrode 104 by printing a thick layered conductor material. A branch 106 is formed, and the working electrode 103 and the auxiliary electrode 104 formed on the upper and lower plates 101 and 102 are symmetrically or about a pressure-adhesive separator 107 having a thickness of about 0.07 mm. Asymmetrically with each other Is isolated from the primary viewing position constitutes the thin-layer electrochemical cell (thin layer electrochemical cell). (See Face electrode: E. K. Bauman et al., Analytical Chemistry, vol 37, p 1378,1965; K. B. Oldham in "Microelectrodes: Theory and Applications," Kluwer Academic Publishers, 1991).

The working electrode 103 is disposed under the pressure-adhesive separator 107 and is defined to have an area of about 1.95 mm 2 by an insulating film 109 coated with a reagent layer 108, and the working electrode 103. On the same plane as the viscometer measuring electrode for measuring the rate at which blood enters against the working electrode 103 can be formed by screen printing, the pressure-adhesive separator 107 is a blood electrode actuation capillary action ( It may be provided with a sample introduction portion (107a) structure to soak well toward the 103.

The upper plate 102 may be formed with an air outlet through which the air in the blood is discharged.

Of course, such a face-type biosensor, Republic of Korea Patent Application 10-2003-0036804, 10-2005-0010720, 10-2007-0020447, 10-2007-0021086, 10-2007-0025106, 10-2007- 0030346 and EK Bauman et al., Analytical Chemistry, vol 37, p 1378, 1965 and KB Oldham in "Microelectrodes: Theory and Applications," Kluwer Academic Publishers, 1991.

On the other hand, the face-type biosensor 100 according to an embodiment of the present invention may be formed by coating the reagent composition with the reagent layer 108 on the insulating film 109.

The face-type biosensor 100 configured as described above has a sample introduction portion 107a with an average value of 0.5 µl.

The reagent composition for measuring glucose level coated on the reagent layer 108 was referred to US7258769. Briefly mentioned, glucose oxidase (FAD-GOx), hexaamineruthenium chloride (Ru (NH3) 6Cl3), and increase First, dispersants were prepared by dissolving in sodium phosphate buffer (pH 6.4, 0.1 M) and adding deionized water.

Of course, as shown in FIG. 2, the portable meter 100 ′ according to an embodiment of the present invention may have a planar biosensor 110 ′.

The planar biosensor 110 ′ has the same working electrode 103 and the auxiliary electrode 104 on one of the upper and lower plates 101 and 102 made of two flat insulating plates made of an insulating material such as synthetic resin, for example, polyester. The working electrode 103 'and the auxiliary electrode 104' formed together with one of the upper and lower plates 101 'and 102' are formed by screen printing with carbon / graphite to be disposed in the pressure. The adhesive separator 107 ′ may be separated to face each other to form a thin layer electrochemical cell.

The working electrode 103 'and the auxiliary electrode 104' have an area of about 1.05 by an insulating film 109 'coated with a sample layer 108' disposed under the pressure-sensitive separator 107 '. The pressure-adhesive separator 107 'may be provided with a sample introduction part 107a' structure to allow blood to permeate well toward the working electrode 103 'by capillary action.

The planar biosensor 110 ′ configured as described above has an average value of 0.5 μl sample introduction portion 107a ′.

As described above, even when the sample introduction portions 107a and 107a 'have a small amount of a sample having an average value of 0.5 μl, the portable measuring instruments 100 and 100' according to an embodiment of the present invention can provide accurate and fast response time. Do.

According to the portable measuring device (100, 100 ') according to an embodiment of the present invention, the concentration of blood substances, hematocrit, temperature and other received current value obtained by applying a voltage to the existing electrochemical biosensors (110, 110') By correcting the effects of interfering substances, the concentration of specific substances in the blood can be accurately corrected.

Hereinafter, a method for measuring the concentration of a specific substance (glucose) in blood used in a portable measuring instrument according to an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

Referring to Figure 3, the method for measuring the concentration of a specific substance in the blood used in the portable measuring instrument according to an embodiment of the present invention to prepare a sample (S110), for example, portable electrochemical facing biosensor 110 The sensor 100 is loaded (S120), and the biosensor 110 contacts the sample (blood) so that blood wets the working electrode 103 and the auxiliary electrode 104 of the electrochemical biosensor 110. At a moment, a constant voltage is applied through the constant voltage applying unit 120 (S130), and a cyclic voltage is continuously applied through the cyclic voltage applying unit 130 at the end of a large time applied voltage after the constant voltage is applied (S140). ).

The cyclic voltage may be a triangular waveform with a simple operation.

The correction processing unit 140 of the portable measuring instrument 100 analyzes the current value displayed by the application of the circulating voltage to the concentration of the substance in the blood displayed by the current value measured by the constant voltage. Correct the influence (S150).

In the method for measuring the concentration of a specific substance in the blood according to an embodiment of the present invention, the specific substance may be glucose.

Referring to FIG. 4, a blood glucose measurement method according to an embodiment of the present invention is applied to a blood sample inhaled by a biosensor continuously applying a circulating voltage following a predetermined voltage (S210), and according to the application of the circulating voltage. Obtaining a current value (S220), and obtaining a correlation coefficient between the current value and the hematocrit and blood glucose in the blood (S230), find at least one or more variables providing information of the hematocrit in the blood (S240), An equation for hematocrit or glucose is derived through an intelligent method or statistical regression analysis (S250), and the effect of the hematocrit is corrected using this equation (S260) to obtain an improved final blood glucose value (S270). ).

Hereinafter, in the method for measuring the concentration of a specific substance in blood according to an embodiment of the present invention with reference to FIGS. 5A to 7, it is used to increase the concentration of a specific substance in blood, in particular blood glucose measurement accuracy. The method for correcting the effect of the generated hematocrit is described in detail.

First, a conventional blood glucose measurement method using the face-type biosensor 100 will be described with reference to FIGS. 5A and 5B.

FIG. 5A is a graph illustrating a change in time-applied voltage (applied voltage vs. time) to explain a blood glucose measurement method according to a comparative example.

FIG. 5B is a graph showing a current value for the glucose standard sample at the end point of time applied voltage of FIG. 5A.

<Comparative Example>

In general, the conventional blood glucose measurement method measures a current value generated by applying a constant voltage to a conventional flat or large surface type electrochemical biosensor through a portable measuring instrument and applying an oxidation potential of a reduced electron transfer medium at a working electrode. The concentration of was determined.

According to a comparative example, the sample of the face-type biosensor 110 is the working electrode 103 and the auxiliary electrode 104 as shown in the graph of FIG. 5A in the face-type electrochemical biosensor 110 as shown in FIG. 1. ) At the same time, a voltage of 0 mV is applied to the working electrode 103, and after waiting for 3 seconds, a voltage of 200 mV is applied to the working electrode 103 for 2 seconds.

The sample is a glucose standard solution, and the glucose standard solution is blood prepared by adjusting blood from vein to hematocrit at 20% to 60% and having various glucose concentrations using a glucose analyzer, that is, 2300 Stat Plus of YSI. In this regard, standard blood samples of 80, 150, 300 and 500 mg / dL concentrations were measured five times each.

By using the glucose standard solution as described above, it is possible to know the difference between the given glucose concentration and the glucose concentration using the large-area electrochemical biosensor 110.

As shown in FIG. 5B, a 20% hematocrit blood sample has a relatively high current value when compared to a 42% blood sample, whereas a blood sample 60% hematocrit is 42% compared to a blood sample. It can be seen that it has a relatively low current value.

In other words, it can be seen that the current value changes according to the amount of hematocrit in the blood and the concentration of blood glucose also varies.

More specifically, a sample with 20% hematocrit has a 10 to 30% higher measurement deviation than a sample with 42%, and a sample with a 60% hematocrit is -10 to -20% lower than a sample with 42% It can be seen that it causes an error.

On the contrary, according to the method for measuring the concentration of a specific substance in the blood according to an embodiment of the present invention, the measurement error according to the hematocrit can be corrected compared to the method for measuring the concentration of the specific substance in the blood according to the comparative example.

According to the experimental example of the blood glucose measurement method according to an embodiment of the present invention to be described later, it will be described with reference to Figure 6a to Figure 7 that can reduce the measurement error compared to the comparative example by correcting the measurement error according to the hematocrit.

FIG. 6A is a graph illustrating the application of the circulating voltage at the end point of the time applied voltage of FIG. 5A, FIG. 6B is a graph showing the change of the time applied voltage in FIG. 6A, and FIG. 6C is a current value for the first cyclic voltage of FIG. 6A. Figure 6d is an enlarged view of the profile, Figure 6d is a graph showing the relationship between the current value and the applied voltage for the second circulating voltage of Figure 6c, Figure 7 is a method of measuring the concentration of a specific substance in the blood according to an embodiment of the present invention It is a graph showing measurement error.

<Experimental Example 1>

In the blood glucose measurement method according to an embodiment of the present invention, as shown in FIG. 6A, similarly to the comparative example, when the sample covers the working electrode 103 and the auxiliary electrode 104 at the same time, the operating electrode 103 is zero. After applying mV, waiting for 3 seconds, a constant voltage (constant voltage) is applied to the working electrode 104 for 200 mV for 2 seconds, and a cyclic voltage for raising and lowering the voltage at a constant cycle between 100 mV and 150 mV at 5 seconds. (cyclic voltage) is applied for 10 1 second fast cycle.

The current value obtained for this voltage application was used to calculate hematocrit using multiple regression analysis represented by the following equation (1).

Hematocrit = β ₀ + β ₁ X ₁ + β ₂ X ₂ +... + β ₈ X ₈ + β ₉ X ₉ +. + ε _h (1)

Wherein β ₀ is a constant β ₁ , β ₂ ,. β ₈ and β ₉ are independent variables X ₁ , X ₂ ,.. Is the coefficient of X ₈ and X ₉ , and ε _h is the error term.

Table 1 shows 11 independent variables that correlate well with the dependent variable hematocrit, the number of which is not limited to the 11 described here.

 Independent variable correlated with hematocrit Symbol of Independent Variables Independent variable Characteristics of the independent variable X ₁ i _5.07 Current value near 100 mV of cyclic voltage part X ₂ i _5.1275 150 mV of current value of cyclic voltage part X ₃ i _5.1775 100mV current value of cyclic voltage part X ₄ i _5.2025 Current value of intermediate voltage (125 mV) of cyclic voltage part X ₅ i _5.2525 Current value of intermediate voltage (125 mV) of cyclic voltage part X ₆ i _5.2275 150mV current value of cyclic voltage part X ₇ (= X ₂ / X ₃ ) (i _5.1275 / i _5.1775 ) Ratio of 150mV current value and 100mV current value of cyclic voltage part X ₈ (= X ₄ / X ₅ ) (i _5.2025 / i _5.2525 ) The ratio of the current value of 125 mV and the current value of 125 mV in the cyclic voltage section X ₉ (= X ₆ / X ₂ ) (i _5.2275 / i _5.1275 ) The ratio of the 150 mV current value to the next 150 mV current value in the cyclic voltage section X ₁₀ i ₅ Last current value of constant voltage X ₁₁ Integral value of current from 5 to 6 seconds Sum of current value of cyclic voltage part ... ...

Where i _x is the current value in x seconds.

6C and 6D illustrate, by way of example, independent variables with high correlation.

6C and 6D, the relationship between the current value profile for the initial cyclic voltage, the current value for the second cyclic voltage, and the applied voltage as shown in FIG. 6A shows that the hematocrit is 20% and the concentration of glucose is 150 mg. For standard solutions of / dL, current value at 125 mV when scanning from low front to high front, i _5.1025 (= 16.58 μA) and current at 125 mV when scanning from high front to low forward i _5.1525 (= 9.56 μA) is 7.02 μA (= 16.58 μA-9.56 μA).

For standard samples with 40% hematocrit, the difference is 6.54 μA (= 14.48 μA-7.94 μA), and for standard samples with 60% hematocrit, the difference is 5.77 μA (= 12.92 μA-7.15 μA).

Therefore, the larger the difference in hematocrit, the larger i _5.1025 and i _5.1525 are useful variables that correlate with hematocrit.

Regression analysis of these variables on hematocrit leads to the following equation (1).

Hematocrit = -3213-31.9 × i _5.2025 + 63.9 × i _5.2525 + 251 × (i _5.2025 / i _5.2525 ) + 143 × i _5.1275-56.0 × i _5.1775-17.4 × (i _5.1275 / i _5.1775 ) + 17.4 × _{i 5.07 - 135 × i 5.2275 +} 2842 × (i 5.2275 / i 5.1275) (2)

The final blood glucose value can be calculated by calculating the hematocrit from Equation (2) above and arithmetic through the current value to determine how much the value affects the measurement of the blood glucose value.

As described above, the method of correcting the influence on the measurement error caused by the hematocrit shows a measurement error as shown in FIG. 7.

As shown in Figure 7, it can be seen that the blood glucose values measured using a portable measuring instrument using a blood sugar measuring method according to an embodiment of the present invention is arranged around the error 0%.

120 face-to-face electrochemical biosensors were repeatedly measured using a portable measuring instrument according to an embodiment of the present invention.

As shown in Table 2, it can be seen that the error range is within 10% for all 120 electrochemical biosensors.

Accuracy of glucose measurement using cyclic voltammetry error range Within ± 5% Within ± 10% Within ± 15% Within ± 20% 88% 100% 100% 100%

As a result, it can be seen that the blood glucose measurement method according to an embodiment of the present invention can increase the accuracy of the blood glucose measurement value by correcting the effect of hematocrit by applying a circulating voltage at the end point of the applied voltage for a long time.

<Experimental Example 2>

Although Experimental Example 1 suggests a method for increasing the accuracy of blood glucose values based on hematocrit in blood samples, the measured current value is not only hematocrit, but also an electrochemically oxidized or reduced interference material present in the sample and the blood sample. Since it is affected by the physical properties of the other samples, the blood glucose value was directly calculated using the following equation without going through the process of deriving the hematocrit as shown in equations (1) and (2).

Glucose = γ0 + γ1X1 + γ2X2 +... + gamma 8X8 + gamma 9X9 +... + εg (3)

Where γ0 is a constant, γ1, γ2,... γ8 and γ9 are independent variables X1, X2,... Is the coefficient of X8 and X9, and εg is the error term.

In addition, in order to increase the reliability of the correction equation, a plurality of regression equations were derived by combining independent variables, and the average of those equations was calculated to calculate blood glucose values, and the results are shown in FIG. 8.

8 is a graph showing a measurement error of the method for measuring the concentration of a specific substance in the blood according to another embodiment of the present invention.

As shown in Figure 8, it can be seen that the blood glucose value measured using a portable measuring instrument using a blood glucose measurement method according to another embodiment of the present invention is arranged around the error 0%.

As a result, the blood glucose measurement method according to an embodiment of the present invention is applied to the electrochemically oxidized or reduced interference materials and other samples present in the blood sample and the temperature of the sample by applying a circulating voltage at the end of the time-applied voltage It can be seen that the accuracy of the blood glucose measurement can be improved by correcting the influence of physical properties.

As shown in Fig. 6B, better hematocrit information can be extracted by changing the time-applied voltage portion or by changing the range and period of the cyclic voltage portion.

Although the blood glucose measurement method according to the exemplary embodiment of the present invention is applied to a large-area biosensor, the flat biosensor is not excluded and detailed description thereof is omitted since the same result was obtained for the flat biosensor.

Claims (12)

Applying a constant voltage after the blood sample is filled to the cell for the cell containing the blood sample, and the electrochemical biosensor having the working electrode and the auxiliary electrode in the cell; Obtaining a characteristic information of the blood sample by linearly combining at least two current values measured corresponding to the predetermined voltage and the circulating voltage, and correcting the influence of the characteristic information of the blood sample. Method for measuring the concentration of the analyte in the blood sample comprising the step. The method of claim 1,
The characteristic information of the blood sample is hematocrit, and the analyte is blood glucose. The method of claim 1,
The characteristic information of the blood sample is analytes that cause redox currents other than redox currents generated by the activity of enzymes and electron transfer mediators, and the analytes are glucose, lactate, cholesterol, Method for measuring the concentration of analyte in blood samples, creatine, creatinine, phenylketone, ketone. The method of claim 1,
The characteristic information of the blood sample is a method for measuring the concentration of an analyte in a blood sample obtained from a current value or a ratio of these current values at the time when the application direction of the circulating voltage changes. The method of claim 1,
Characteristic information of the blood sample is a method of measuring the concentration of the analyte in the blood sample obtained from the current value of the intermediate voltage of the circulating voltage or the ratio of these current values. The method of claim 1,
Characteristic information of the blood sample is a method of measuring the concentration of the analyte in the blood sample obtained from the sum of the current values for the circulating voltage. The method of claim 1,
The constant voltage is a constant voltage, the circulating voltage is made by a linear scan method and by varying the range and period of the constant voltage and the circulating voltage to extract at least one or more characteristic information of the blood sample, Method for measuring the concentration of analyte in blood samples with corrected characteristics. 3. The method of claim 2,
The hematocrit is calculated by using the current value according to the application of the cyclic voltage calculated according to Equation (1),
Hematocrit =

+ ε _h (1)
here

Is the linear coupling coefficient obtained from the regression analysis.

Is a current value or ratio of current values at various points measured while an applied voltage is applied, ε _h is an error term, and N is a positive integer. The method of claim 3, wherein
The amount of the analyte disturbance is calculated using the current value according to the application of the cyclic voltage calculated according to equation (1),
Hematocrit =

+ ε _h (2)
here,

Is the linear coupling coefficient obtained from the regression analysis.

Is a current value or ratio of current values at various points measured while an applied voltage is applied, ε _h is an error term, and N is a positive integer. The method of claim 3, wherein
The glucose is calculated using the current value according to the application of the cyclic voltage calculated according to equation (3),
Glucose =

+ εg (3)
here

Is the regression coefficient of the linear combination equation,

Is the current value or ratio of current values at various points measured while the applied voltage is applied, εg is the error term, and N is the positive integer, the concentration of the analyte in the blood sample corrected for the influence of a specific interfering substance in the blood. How to measure. In a portable measuring instrument using the method for measuring the concentration of a specific substance in the blood according to any one of claims 1 to 10,
The constant voltage applying unit and the circulating voltage applying unit for applying a constant voltage according to the method for measuring the concentration of the analyte in the blood sample according to any one of claims 1 to 10 for the electrochemical biosensor, and the constant voltage When the applying unit applies a constant voltage to the electrochemical biosensor, the current value according to the redox reaction of the enzyme and the electron transfer medium of the electrochemical biosensor and the cyclic voltage applied by the circulating voltage applying unit Portable measuring instrument including a correction processing unit for correcting the influence of the characteristic information of the blood sample through the analysis. The method of claim 11,
The correction processing unit
Correcting the effect of hematocrit is
Reading current values according to the application of a cyclic voltage by a linear scan method,
Obtaining a correlation coefficient between the current values and the hematocrit in the blood sample;
Obtaining at least one variable for providing information of the hematocrit in the blood sample using the correlation coefficient;
Regressing the variable to derive an equation for hematocrit;
Subtracting a value that affects the current values by the hematocrit from the current value,
A portable instrument comprising a concentration measurement program of the analyte in the blood sample comprising the step of obtaining the concentration of the analyte in the blood sample by the current value.

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