TWI652478B - Method of measuring hematocrit and method of testing blood - Google Patents

Abstract

The invention provides a method for measuring the volume ratio of blood cells and a method for detecting blood. The method of measuring the hematocrit ratio includes the following steps. Provide test strips. The test strip includes a reaction zone and a pair of electrodes disposed in the reaction zone. The whole blood sample is allowed to enter the reaction zone. After the whole blood sample enters the reaction zone, a set of square wave voltages are applied to the pair of electrodes by square wave voltammetry to obtain a feedback value associated with the hematocrit ratio. The start time point at which the whole blood sample enters the reaction zone differs from the start time point at which a set of square wave voltages is applied by 0.1 second to 200 seconds. The blood cell volume ratio is calculated based on the feedback value.

Description

Blood volume ratio measurement method and blood detection method

The present invention relates to a blood cell volume ratio measuring method and a blood detecting method, and to a blood cell volume ratio measuring method and a blood detecting method for a whole blood sample.

Hematocrit (Hct) mainly refers to the proportion of blood cells (mainly red blood cells) precipitated in whole blood after centrifugation of whole blood supplemented with anticoagulant. For clinical laboratory testing machines, plasma is used as a test sample. In other words, the blood is first centrifuged, and the obtained plasma is used for detection. As a result, the difference in blood cell volume ratio does not cause interference to the test results.

However, for point of care testing (POCT) or patient over-counter (OTC) testing machines, in order to reduce the time and cost required for testing, it is generally used The blood sample is directly measured. That is to say, the hematocrit ratio with individual differences can cause errors in detection. In addition, the temperature and humidity of the sample storage or the temperature and humidity when the machine is tested can affect the blood cell volume ratio detection result.

Embodiments of the present invention provide a method for measuring a blood cell volume ratio, including the following steps. Provide test strips. The test strip includes a reaction zone and a pair of electrodes disposed in the reaction zone. The whole blood sample is allowed to enter the reaction zone. After the whole blood sample enters the reaction zone, a square wave voltage is applied to the pair of electrodes by square wave voltammetry to obtain a feedback value associated with the hematocrit ratio. The start time point at which the whole blood sample enters the reaction zone differs from the start time point at which a set of square wave voltages is applied by 0.1 second to 200 seconds. The blood cell volume ratio is calculated based on the feedback value.

Embodiments of the present invention provide a blood detection method including the following steps. Provide test strips. The test strip includes a first reaction zone, a pair of first electrodes disposed in the first reaction zone, a second reaction zone, and a pair of second electrodes disposed in the second reaction zone. The whole blood sample is passed into the first reaction zone and the second reaction zone. After the whole blood sample enters the first reaction zone, two sets of square wave voltages are applied to the pair of first electrodes by square wave voltammetry to obtain a first feedback value and a second feedback value respectively associated with the hematocrit ratio. A voltage is applied to a pair of second electrodes to obtain a third feedback value to estimate the concentration of the target analyte in the whole blood sample. It is determined whether the ratio of the first feedback value to the second feedback value is between preset ranges. If the ratio of the first feedback value to the second feedback value is between the preset ranges, the concentration of the target analyte is used, and otherwise the message for detecting the abnormality is provided.

Embodiments of the present invention provide a method for measuring a blood cell volume ratio, including the following steps. Provide test strips. The test strip includes a reaction zone and a pair of electrodes disposed in the reaction zone. The whole blood sample is allowed to enter the reaction zone. Applying multiple sets of square wave voltages to a pair of electrodes by square wave voltammetry to obtain multiple feedbacks related to the hematocrit ratio value. The interval between adjacent two groups of square wave voltages is from 0.1 second to 4 seconds. The feedback value of the nth group square wave voltage is obtained to calculate the hematocrit ratio of the whole blood sample. n is a positive integer greater than one.

Embodiments of the present invention provide a blood detection method including the following steps. Provide test strips. The test strip includes a first reaction zone, a pair of first electrodes disposed in the first reaction zone, a second reaction zone, and a pair of second electrodes disposed in the second reaction zone. The whole blood sample is passed into the first reaction zone and the second reaction zone. A plurality of sets of square wave voltages are continuously applied to a pair of first electrodes by square wave voltammetry to obtain a plurality of feedback values related to the hematocrit ratio. A voltage is applied to a pair of second electrodes to estimate the concentration of the target analyte in the whole blood sample. It is judged whether the ratio of any two feedback values of the square wave voltage after the first group is between the preset ranges. If the ratio of any two feedback values of the square wave voltage after the first group is between the preset ranges, the concentration of the target analyte is used, and vice versa, a message for detecting the abnormality is provided.

The above described features and advantages of the invention will be apparent from the following description.

200‧‧‧Test strips

202‧‧‧First reaction zone

204‧‧‧First electrode

204a‧‧‧First working electrode

204b‧‧‧First reference electrode

206‧‧‧Second reaction zone

208‧‧‧second electrode

208a‧‧‧second working electrode

208b‧‧‧second reference electrode

Lines A, B, C, D‧‧

Amp‧‧‧ amplitude

E‧‧‧ sample injection

E _final ‧‧‧target voltage

E _incr ‧‧‧Increased voltage

E _init ‧‧‧ initial voltage

F‧‧‧frequency

S100, S100a, S102, S102a, S104, S104a, S106, S108, S110, S112, S114, S504, S504a, S506, S508, S510, S512, S514‧‧

T0, T1, T2, T3, TS1‧‧‧ starting point

V1, V2, VS‧‧‧ square wave voltage

V3, V3’‧‧‧ voltage

1A and FIG. 1B are respectively a flow chart of a method for measuring a blood volume ratio and a flow chart of a blood detecting method according to an embodiment of the present invention.

2 is a top plan view of a test strip in accordance with an embodiment of the present invention.

3 is a graph showing the voltage variation of a square wave voltammetry according to an embodiment of the invention. Schematic diagram.

4 is a schematic illustration of the sequence of blood cell volume ratio and target analyte concentration measurements for whole blood samples in accordance with the embodiment illustrated in FIGS. 1A and 1B.

5A and 5B are respectively a flow chart of a method for measuring a blood volume ratio and a flow chart of a blood detecting method according to another embodiment of the present invention.

Figure 6 is a schematic illustration of the sequence of blood cell volume ratio and target analyte concentration detection for a whole blood sample in accordance with the embodiment illustrated in Figures 5A and 5B.

Figure 7 is a plot of the feedback value of the wave voltage versus the hematocrit ratio for different humidity levels in accordance with an experimental example of the present invention.

Figure 8 is a plot of the feedback value of the wave voltage versus the hematocrit ratio for different humidity levels in accordance with a comparative example.

1A and FIG. 1B are respectively a flow chart of a method for measuring a blood volume ratio and a flow chart of a blood detecting method according to an embodiment of the present invention. 2 is a top plan view of a test strip in accordance with an embodiment of the present invention. 3 is a graph showing voltage versus time for square wave voltammetry in accordance with an embodiment of the present invention. 4 is a schematic illustration of the sequence of blood cell volume ratio and target analyte concentration detection for a whole blood sample in accordance with the embodiment illustrated in FIGS. 1A and 1B.

Referring to FIG. 1A and FIG. 2, a method for measuring a hematocrit (Hct) ratio according to an embodiment of the present invention includes the following steps.

Step S100 is performed to provide the test strip 200. The test strip 200 includes The first reaction zone 202 and a pair of first electrodes 204 disposed in the first reaction zone 202. In some embodiments, a pair of first electrodes 204 includes a first working electrode 204a and a first reference electrode 204b. The first reaction region 202 may be located on the first working electrode 204a and the first reference electrode 204b, and expose a portion of the first working electrode 204a and the first reference electrode 204b. In some embodiments, the test strip 200 further includes a second reaction zone 206 and a pair of second electrodes 208 disposed in the second reaction zone 206. The pair of second electrodes 208 may include a second working electrode 208a and a second reference electrode 208b. The second reaction region 206 may be located on the second working electrode 208a and the second reference electrode 208b, and expose a portion of the second working electrode 208a and the second reference electrode 208b.

After the whole blood sample enters the test strip 200 and passes through the first reaction zone 202 (or the first reaction zone 202 and the second reaction zone 206), the first electrode 204 (or the first electrode 204 and the second electrode 208) can receive The whole blood sample is reacted in the first reaction zone 202 (or the first reaction zone 202 and the second reaction zone 206) with a voltage. In some embodiments, the first reference electrode 204b can be electrically connected to the second reference electrode 208b, or the pair of first electrodes 204 and the pair of second electrodes 208 can share the same reference electrode. In some embodiments, the second reference electrode 208b (or a reference electrode that can be shared with the first reference electrode 204b) can detect the amount of whole blood sample entering the test strip 200. Accordingly, the amount of the whole blood sample is sufficient to apply a voltage to the first working electrode 204a and the second working electrode 208a, and the whole blood sample starts to react in the first reaction zone 202 and the second reaction zone 206.

In some embodiments, the first reaction zone 202 can be closer to the sample injection site E of the test strip 200 than the second reaction zone 206. In addition, the first reaction zone 202 and The second reaction zone 206 can be disposed in the same channel. However, in other embodiments, the second reaction zone 206 can also be closer to the sample injection site E than the first reaction zone 202. In addition, the first reaction zone 202 and the second reaction zone 206 may be disposed on the left and right sides or in different planes. Furthermore, the first reaction zone 202 and the second reaction zone 206 can be disposed in different channels. The relative positional relationship between the first reaction zone 202 and the second reaction zone 206 can be adjusted according to the design requirements, and the invention is not limited thereto.

In some embodiments, the distance between the first working electrode 204a and the first reference electrode 204b ranges from 0.01 mm to 5 mm. For example, the distance between the first working electrode 204a and the first reference electrode 204b may range from 0.01 mm to 1 mm, or from 0.05 mm to 5 mm. Further, the ratio of the area of the first working electrode 204a to the area of the first reference electrode 204b ranges from 1 to 1.5. For example, the ratio of the area of the first working electrode 204a to the area of the first reference electrode 204b may range from 1 to 1.2. By controlling the pitch and area ratio of the first working electrode 204a and the first reference electrode 204b within the above range, a stable feedback value can be obtained when a voltage is applied to the first working electrode 204a.

In some embodiments, the reagents can be disposed on the second reaction zone 206. The material of the reaction reagent may include a reaction enzyme, and may further include an electron vehicle. In other embodiments, the reagents may further extend to the first reaction zone 202.

Step S102 is performed to allow the whole blood sample to enter the first reaction zone 202. Specifically, the whole blood sample can be entered from the sample injection site E of the test strip 200 by capillary force or microchannel design. In addition, the whole blood sample enters the first reaction zone 202, More access to the second reaction zone 206 is possible.

Referring to FIG. 1A and FIG. 2 to FIG. 4, step S104 is followed to apply a set of square wave voltage V1 to a pair of first electrodes 204 by square wave voltammetry (SWV) to obtain a blood cell volume. The first feedback value. In this way, the first working electrode 204a can receive the square wave voltage V1 to electrically react the whole blood sample in the first reaction zone 202 to obtain a first feedback value. In particular, the first feedback value is a current value. As shown in FIG. 3, the square wave voltage V1 can be a positive voltage, and its initial voltage E _init gradually increases toward the target voltage E _{final with an} increasing voltage E _incr over time. Specifically, the square wave voltage V1 is centered on the initial voltage E _init , and a positive and negative voltage oscillation of a fixed voltage amplitude Amp is applied via the fixed frequency F. Next, a fixed amplification voltage E _{incr is added} , and the oscillation of the fixed voltage amplitude is centered on the new voltage value (E _init + E _incr ) until the center of the voltage value reaches the target voltage E _final .

In the case of giving parameters such as an appropriate amplitude Amp, frequency F, and amplification voltage E _incr , the first feedback value about the hematocrit ratio produced by the whole blood sample can be stably measured. In some embodiments, the square wave voltage V1 can have a fixed amplitude Amp, a frequency F, and an amplification voltage E _incr . For example, the frequency F can be greater than 100 Hz, for example in the range of 100 Hz to 4000 Hz. The amplitude Amp may be greater than or equal to 0.01 V, for example, in the range of 0.01 V to 0.4 V. The amplification voltage E _incr may be in the range of 0.01 V to 0.4 V, for example, in the range of 0.05 V to 0.2 V. In addition to this, the scanning range of the square wave voltage V1 can be between 0V and 0.8V. Further, the time period during which the voltage is applied may be in the range of 0.01 second to 4 seconds, for example, in the range of 0.01 second to 2 seconds.

However, those having ordinary skill in the art can adjust the above parameters according to changes in the materials, patterns, positions, and the like of the first electrode 204. For example, when the material of the first electrode 204 is a carbon ink (for example, a screen printed carbon electrode (SPCE)), the frequency F of the square wave voltage V1 may range from 100 Hz to 500 Hz, and the amplitude The Amp range can be from 0.01V to 0.4V. Further, the voltage sweep range of the square wave voltage V1 may be 0V to 0.5V, and the application time of the square wave voltage V1 may be 0.01 second to 2 seconds. As another example, when the material of the first electrode 204 is gold, the frequency F of the square wave voltage V1 may range from 500 Hz to 4000 Hz, and the amplitude Amp may range from 0.1 V to 0.4 V. Further, the voltage sweep range of the square wave voltage V1 may be 0V to 0.5V, and the application time of the square wave voltage V1 may be 0.01 second to 2 seconds.

Referring to FIG. 3 and FIG. 4, the interval between the start time T0 of the whole blood sample entering the first reaction zone 202 of the test strip 200 and the start time T1 of applying a set of square wave voltage V1 to the first electrode 204 is 0.1 seconds to 200 seconds. In some embodiments, the interval between the start time T0 and the start time T1 may also be 0.1 second to 120 seconds, 0.1 second to 60 seconds, 0.1 second to 30 seconds, 0.1 second to 10 seconds, and 0.1 second to 5 seconds. Seconds, 0.1 second to 1 second, 1 second to 200 seconds, 3 seconds to 200 seconds or 5 seconds to 200 seconds, 10 seconds to 200 seconds, 20 seconds to 200 seconds, 50 seconds to 200 seconds, 1 second to 120 seconds , 3 seconds to 60 seconds, 5 seconds to 30 seconds, or 5 seconds to 10 seconds.

Step S106 is performed to calculate a blood cell volume ratio based on the first feedback value. It has been found through experimentation that the first feedback value (current value) has a negative correlation with the hematocrit ratio. Counting the first feedback value for a whole blood sample with different known hematocrit ratios, The negative correlations described are summarized as a relationship. This relationship can include polynomial or linear relationships. Subsequently, a first hedging value for a whole blood sample having an unknown hematocrit ratio is substituted into the relationship to obtain a corresponding hematocrit ratio.

It is to be noted that when the test strip 200 is exposed to the atmosphere, it is easy to form a water film on the first electrode 204 (or on the first electrode 204 and the second electrode 208). In addition, when the whole blood sample enters the first reaction zone 202 of the test strip 200 (or enters the first reaction zone 202 and the second reaction zone 206), it is easy to be between the whole blood sample and the first electrode 204 (and the whole blood sample) Microbubbles are generated between the second electrode 208 and the second electrode 208. This water film and microbubbles can cause errors in the measurement of the hematocrit ratio. In this embodiment, by applying a set of square wave voltage V1 to the first electrode 204 by the square wave voltammetry after the whole blood sample stays in the first reaction zone 202 for an interval, the whole blood sample and the first electrode 204 can be destroyed. Water film and microbubbles (and between the whole blood sample and the second electrode 208). In this way, the influence of moisture and microbubbles in the environment on the measurement of the hematocrit ratio can be avoided. In addition, when the present invention uses the square wave voltammetry to measure the hematocrit ratio, it is less susceptible to the concentration of the target analyte (for example, blood glucose). Therefore, the method of the present invention can effectively reduce the influence of humidity, microbubbles and target analyte concentration on the error of blood cell volume ratio measurement.

Referring to FIG. 1B and FIG. 2 to FIG. 4, the blood detecting method of the present embodiment includes the following steps. The blood detecting method of the present embodiment includes a partial measuring method of the hematocrit ratio shown in FIG. 1A, and the same or similar portions will not be described again. In addition, similar steps are denoted by like reference numerals.

Step S100a is performed to provide the test strip 200. As shown in Figure 2, detection The test strip 200 includes a first reaction zone 202, a pair of first electrodes 204 disposed in the first reaction zone 202, a second reaction zone 206, and a pair of second electrodes 208 disposed in the second reaction zone 206.

Step S102a is performed to allow the whole blood sample to enter the first reaction zone 202 and the second reaction zone 206. Next, in step S104a, a square wave voltage V1 and a set of square wave voltage V2 are applied to the first electrode 204 by square wave voltammetry to obtain a first feedback value and a second feedback value respectively related to the hematocrit ratio. . Specifically, the first working electrode 204a can receive the square wave voltage V1 and the square wave voltage V2, respectively, and the whole blood sample is electrically reacted in the first reaction zone 202 to obtain a first feedback about the blood cell volume ratio. The value and the second feedback value. Further, the square wave voltage V2 is similar to the square wave voltage V1, and the difference between the two is only different at the time point of application. In particular, the start time T1 at which the square wave voltage V1 is applied is earlier than the start time T2 at which the square wave voltage V2 is applied. In some embodiments, the interval between the start time T1 of the square wave voltage V1 and the start time T2 of the square wave voltage V2 may be 0.1 second to 200 seconds. In other embodiments, the interval between the start time T1 of the square wave voltage V1 and the start time T2 of the square wave voltage V2 may be 0.1 second to 3 seconds.

Step S108 is performed to apply a voltage V3 to the second electrode 208 to obtain a third feedback value to estimate the concentration of the target analyte in the whole blood sample. In some embodiments, the voltage V3 can be applied to the second electrode 208 after application of the square wave voltage V1 or prior to application. In other embodiments, the voltage V3 may also be applied to the second electrode 208 after a period of application of the square wave voltage V1 or immediately. In another embodiment, the voltage V3 may be applied to the second electrode 208 after the square wave voltage V2 is applied. Special attention Yes, the applied voltage V3 can be performed independently of any time, and the invention is not limited thereto. The method of applying the voltage V3 to the second electrode 208 may include amperometry, coulometry, potentiometry, voltammetry, impedance, or a combination thereof, and the present invention Not limited to this. In some embodiments, the analyte of interest comprises blood glucose, glycated hemoglobin (HbA1c), blood lactate, cholesterol, uric acid, triglycerides, coagulation factors, or anticoagulants.

The method for estimating the concentration of the target analyte in the whole blood sample by using the third feedback value comprises first deriving the blood volume ratio in the whole blood sample according to at least one of the first feedback value and the second feedback value (FIG. 1A) Step S106). In some embodiments, the first feedback value, the second feedback value, or both averages may be selected to derive a hematocrit ratio in the whole blood sample. Next, the concentration of the target analyte is calculated based on the calculated hematocrit ratio and the third feedback value. The detection of whole blood samples with different hematocrit ratios can be concluded that the concentration of the target analyte has a different linear relationship for the third feedback value. The relationship between the slope relationship and the constant term relationship between the linear relationships described above can be corrected according to the calculated hematocrit ratio, and a general formula of the concentration of the target analyte for the third feedback value can be obtained. Accordingly, the third feedback value can be substituted into the general formula to obtain the concentration of the target analyte.

Next, proceeding to step S110, determining whether the ratio of the first feedback value to the second feedback value is between the preset ranges. In some embodiments, the preset range can be from 0.85 to 1.18. If the ratio of the first feedback value to the second feedback value is between the preset ranges, then step S112 is performed to use the calculated concentration of the target analyte. On the contrary, if the first If the ratio of the feedback value to the second feedback value is less than or greater than the preset range, then step S114 is performed to provide a message for detecting an abnormality. In other words, if the ratio of the first feedback value to the second feedback value is between the preset ranges, the calculated concentration of the target analyte is used, and vice versa. In this way, the interference of external factors on the concentration of the analyte of the detection target can be eliminated, and the risk of misjudgment can be reduced. In general, the external factors described above may include changes in temperature and humidity in the environment, or detection defects in the test strip 200.

Based on the above, the blood cell volume ratio measuring method of the present embodiment applies the square wave voltage V1 to the first electrode 204 by square wave voltammetry after the whole blood sample stays in the first reaction zone 202 for an interval. In this way, the water film and microbubbles between the whole blood sample and the first electrode 204 (and between the whole blood sample and the second electrode 208) can be destroyed. Therefore, it is possible to avoid the influence of moisture and microbubbles in the environment on the measurement of the hematocrit ratio, and the square wave voltammetry is also less susceptible to the target analyte concentration, so that a more accurate hematocrit ratio can be obtained. On the other hand, the blood detecting method of the present embodiment includes estimating the concentration of the target analyte in the whole blood sample from the blood cell volume ratio obtained above and the third feedback value obtained by applying the voltage V3 to the second electrode 208. In addition, by determining whether the ratio of the first feedback value and the second feedback value falls within a specific range, determining whether to use the concentration of the target analyte calculated by the third feedback value, the external factor can be excluded from analyzing the detection target. Interference caused by the concentration of matter.

5A and 5B are respectively a flow chart of a method for measuring a blood volume ratio and a flow chart of a blood detecting method according to another embodiment of the present invention. Figure 6 is a schematic illustration of the sequence of blood cell volume ratio and target analyte concentration detection for a whole blood sample in accordance with the embodiment illustrated in Figures 5A and 5B.

Referring to FIG. 5A and FIG. 6, the blood cell volume ratio measuring method according to another embodiment of the present invention is similar to the blood cell volume ratio measuring method shown in FIG. 1A. The following only describes the differences between the two, and the same or similar parts will not be described again.

Referring to FIG. 2, FIG. 5A and FIG. 6, after performing step S100 and step S102, step S504 is performed to continuously apply a plurality of sets of square wave voltages to the first electrode 204 by square wave voltammetry (as shown in FIG. 6). Group square wave voltage VS). The interval between adjacent two groups of square wave voltages VS is from 0.1 second to 4 seconds. Each set of square wave voltages VS can be identical to the square wave voltage V1 shown in FIG. 3, which differs from each other only in the point in time of application. In this way, the first working electrode 204a can receive a continuous plurality of sets of square wave voltages VS to electrically react the whole blood sample in the first reaction zone 202 to obtain a plurality of feedback values related to the hematocrit ratio.

In some embodiments, the start time point T0 at which the whole blood sample enters the first reaction zone 202 (or enters the first reaction zone 202 and the second reaction zone 206) is equal to applying the first set of square wave voltages VS to the first electrode 204. The starting point is TS1. For example, the starting time point T0 is the time point at which the amount of the whole blood sample reaches a threshold value in the first reaction zone 202 (or the first reaction zone 202 and the second reaction zone 206). Those having ordinary knowledge in the art can adjust the threshold according to the detection requirement, and the invention is not limited thereto. In other words, in the above embodiment, when the whole blood sample enters the first reaction zone 202 (or the first reaction zone 202 and the second reaction zone 206), the first set of square wave voltages VS are applied to the first electrode 204. . In other embodiments, the first set of square wave voltages VS may be applied to the first electrode 204 after the whole blood sample fills the first reaction zone 202 (or enters the first reaction zone 202 and the second reaction zone 206). . In other words, the beginning The time point TS1 can also be after the start time point T0. A person having ordinary knowledge in the art can adjust the sequence of the start time point TS1 and the start time point T0 according to the detection requirement, and the present invention is not limited thereto.

Step S506 is performed to obtain a feedback value of the n-th group square wave voltage VS to calculate a blood cell volume ratio of the whole blood sample. n is a positive integer greater than one. In some embodiments, the feedback value of the nth group of square wave voltages VS includes the feedback value of any group of square wave voltages VS after the first group, or the average feedback of the plurality of groups of square wave voltages VS after the first group. value. The reason for taking the feedback value of the square wave voltage VS after the first group may include that the feedback value of the first group square wave voltage VS is more susceptible to the external environment. In other words, the feedback value of the square wave voltage VS after the first group can be stabilized, and a more accurate hematocrit ratio can be derived therefrom. In some embodiments, n is a positive integer greater than or equal to 3. A person having ordinary knowledge in the art can select any one of the group wave feedbacks VS or the plurality of groups of average feedback values after the first group to calculate the hematocrit ratio according to the measurement condition, and the present invention is not limited thereto. Further, a method of estimating the blood cell volume ratio by the feedback value of the nth group square wave voltage VS can be referred to the related description of step S106 of FIG. 1A.

Similar to the measurement method of the hematocrit ratio shown in FIG. 1A, the method for measuring the hematocrit ratio of the present embodiment can also destroy the whole blood sample and the first electrode 204 by applying the square wave voltage VS multiple times ( And a water film and microbubbles between the whole blood sample and the second electrode 208). Therefore, it is possible to avoid the influence of moisture and microbubbles in the environment on the measurement result of the blood volume ratio.

Referring to FIG. 5B and FIG. 6, the blood detecting method of this embodiment is similar to the figure. The blood detecting method shown in 1B, and including the blood cell volume ratio measuring method shown in Fig. 5A. For the sake of brevity, the same or similar parts will not be described again.

After step S100a and step S102a are performed, step S504a is performed to continuously apply a plurality of sets of square wave voltages VS to the first electrode 204 by square wave voltammetry. The interval between the two groups of square wave voltages is from 0.1 second to 4 seconds. Each set of square wave voltages VS can be identical to the square wave voltage V1 shown in FIG. 3, which differs from each other only in the point in time of application. In this way, the first working electrode 204a can receive a continuous plurality of sets of square wave voltages VS to electrically react the whole blood sample in the first reaction zone 202 to obtain a plurality of feedback values related to the hematocrit ratio.

Step S508 is performed to apply a voltage V3' to the second electrode 208 to estimate the concentration of the target analyte in the whole blood sample. In some embodiments, the start time point TS1 of the first group of square wave voltages VS may precede the start time point T3 of the voltage V3'. The start time point TS1 of the first group square wave voltage VS may be equivalent to the start time point T0 at which the whole blood sample enters the first reaction zone 202, or may be after the start time point T0. Furthermore, the starting time point T3 of the voltage V3' may be after the nth group of square wave voltages VS. n is a positive integer greater than one. In some embodiments, n is a positive integer greater than or equal to 3. In other embodiments, the starting time point TS1 of the first group of square wave voltages VS may be after the starting time point T3 of the voltage V3', or may be equal to the starting time point T3 of the voltage V3', the present invention does not This is limited.

In step S508, the method for estimating the concentration of the target analyte in the whole blood sample may include calculating according to the feedback value of any group of square wave voltages VS after the first group or the average feedback value of the plurality of groups of square wave voltages VS. Hematocrit ratio in whole blood samples. Connect The general formula of the feedback value of the concentration of the target analyte to the voltage V3' is obtained in a manner similar to the step S108 shown in Fig. 1B. According to this, the feedback value of the voltage V3' can be substituted into the above formula to obtain the concentration of the target analyte.

Step S510 is performed to determine whether the ratio of any two feedback values of the square wave voltage after the first group is between the preset ranges. In some embodiments, the preset range is from 0.85 to 1.18.

If the ratio of any two feedback values of the square wave voltages after the first group is between the preset ranges, step S512 is performed to calculate the calculated concentration of the target analyte. On the other hand, if the ratio of any two feedback values of the square wave voltage after the first group is not between the preset ranges, but is smaller or larger than the preset range, step S514 is performed to provide a message for detecting an abnormality.

Similar to the blood detecting method shown in FIG. 1B, the blood detecting method of the present embodiment can also eliminate the interference of external factors on the detection target analyte concentration by steps S510, S512, and S514.

Next, the effects of the embodiments of the present invention will be described by way of experimental examples and comparative examples.

<Experimental Example 1>

Step S100, step S102, and step S104 shown in FIG. 1A are sequentially performed for whole blood samples having different hematocrit ratios and different blood sugar contents. Referring to FIGS. 2 to 4, the initial voltage Einit of the square wave voltage V1 of Experimental Example 1 is 0 V, the fixed voltage amplitude Amp is 0.01 V, the amplification voltage Eincr is 0.01 V, and the frequency F is 300 Hz. In addition, the whole blood sample enters the first reaction zone 202 of the test strip 200. The interval between the start time T0 and the start time T1 at which the set of square wave voltage V1 is applied to the first electrode 204 is 0.5 second.

<Comparative Example 1>

In Comparative Example 1, a voltage was applied to a whole blood sample having different hematocrit ratios and different blood sugar contents by differential pulse voltammetry to obtain a feedback value. The differential voltage voltammetry of Comparative Example 1 had an initial voltage of 0 V, a fixed voltage amplitude of 0.05 V, an amplification voltage of 0.045 V, and an interval time of 0.02 sec. Further, the interval between the start time of the whole blood sample entering the first reaction zone 202 of the test strip 200 and the start time of applying the voltage to the first electrode 204 by differential pulse voltammetry is 0.5 second.

<Comparison of Experimental Example 1 and Comparative Example 1>

Table 1 below summarizes the results of Experimental Example 1, and Table 2 below summarizes the results of Comparative Example 1.

Table 2

As can be seen from the above Table 1 and Table 2, in Comparative Example 1 using the differential pulse voltammetry, the current feedback value obtained by the same blood glucose concentration sample can distinguish the difference in the hematocrit ratio in the sample, but in the same hematocrit volume. In the samples with different blood glucose levels, the current feedback value obtained by differential pulse voltammetry is significantly positively correlated with the blood glucose content in the sample, and this relationship with the blood glucose content is positively correlated with the square wave voltammetry. The experimental example 1 of the method is less obvious. It can be seen that square wave voltammetry is less sensitive to blood glucose content in whole blood samples than differential pulse method. Therefore, when the blood volume ratio in the sample is measured, it is less affected by the current change caused by blood glucose concentration. Disturbance, which can more accurately measure the hematocrit ratio of whole blood samples.

<Experimental Example 2>

The whole blood sample A to the whole blood sample E which are known to have different hematocrit ratios are respectively subjected to step S100, step S102, and step S104 as shown in FIG. 1A. The known hematocrit ratio of whole blood sample A is 20%, the known hematocrit ratio of whole blood sample B is 31%, the known hematocrit ratio of whole blood sample C is 40%, and the known blood cell of whole blood sample D is The volume ratio was 51% and the known hematocrit ratio of whole blood sample E was 60%. Referring to FIGS. 2 to 4, the initial voltage Einit of the square wave voltage V1 of Experimental Example 2 is 0.15 V, the fixed voltage amplitude Amp is 0.17 V, the amplification voltage Eincr is 0.04 V, and the frequency F is 750 Hz. Further, the interval between the start time T0 of the whole blood sample entering the first reaction zone 202 of the test strip 200 and the start time T1 of applying the set of square wave voltage V1 to the first electrode 204 is 5 seconds.

<Comparative Example 2>

Comparative Example 2 is similar to Experimental Example 2 except that the start time T0 of the comparative example is equal to the start time T1, that is, there is no interval between the start time T0 and the start time T1. As such, when the whole blood sample enters the first reaction zone 202 of the test strip 200, the square wave voltage V1 is applied to the first electrode 204 immediately.

<Comparison of Experimental Example 2 and Comparative Example 2>

Table 3 below summarizes the results of Experimental Example 2 and Comparative Example 2.

In general, the feedback value of the square wave voltage is inversely related to the hematocrit ratio of the whole blood sample. As can be seen from the above Table 3, the results of Experimental Example 2 can conform to the above negative correlation. In comparison, the above negative correlation cannot be observed from the results of Comparative Example 2. Therefore, it can be known that after the whole blood sample stays in the first reaction zone 202 for an interval time, a square wave voltage V1 is applied to the first electrode 204 by square wave voltammetry, thereby increasing the blood volume ratio and/or performing the measurement. The accuracy of blood testing.

<Experimental Example 3>

In Experimental Example 3, steps S100, S102, and S504 shown in FIG. 5A were sequentially performed in different humidity environments. In Experimental Example 3, a plurality of sets of square wave voltages VS were continuously applied to the first electrode by square wave voltammetry, and the interval between adjacent two groups of square wave voltages VS was 1 second. Next, the blood cell volume ratio of the whole blood sample is estimated from the feedback value of the third group square wave voltage VS. Before performing the above steps, the machine for applying a voltage to the first electrode 204 of the test strip 200 was placed in an environment having a humidity of 31%, 60%, and 90%, respectively, and equilibrated for 30 minutes. Immediately thereafter, the above-described step S100, step S102, and step S504 are performed for the whole blood samples having different hematocrit ratios (the blood cell volume ratios are 20%, 31%, 40%, 50%, and 59%, respectively). In step S504, the initial voltage E _init of the square wave voltage VS is 0.1 V, and the target voltage E _final is 0.4 V.

Fig. 7 is a graph showing the ratio of the feedback value of the wave voltage to the blood cell volume ratio in Experimental Example 3 according to the present invention.

The ordinate of Fig. 7 is the feedback value of the square wave voltage VS, and the abscissa is the hematocrit ratio. In addition, the square data points represent the third feedback value of the square wave voltage VS with a relative humidity of 60%, the circular data points represent the third feedback value of the square wave voltage VS for the relative humidity of 31%, and the triangular data points represent The third feedback value of the square wave voltage VS with a relative humidity of 90%.

<Comparative Example 3> Comparative Example 3 is similar to Experimental Example 3 except that Comparative Example 3 estimates the hematocrit ratio of the whole blood sample by taking the feedback value of the square wave voltage VS of the first group.

Fig. 8 is a graph showing the ratio of the feedback value of the wave voltage to the hematocrit ratio in the lower humidity according to Comparative Example 3.

The ordinate of Fig. 8 is the feedback value of the square wave voltage VS, and the abscissa is the hematocrit ratio. In addition, the square data points represent the first feedback value of the square wave voltage VS with a relative humidity of 90%, the circular data points represent the first feedback value of the square wave voltage VS for the relative humidity of 60%, and the triangular data points represent The first feedback value of the square wave voltage VS with a relative humidity of 31%.

<Comparison of Experimental Example 3 and Comparative Example 3>

Table 4 below summarizes the data of Experimental Example 3 shown in Fig. 7, and Table 5 below summarizes the data of Comparative Example 3 shown in Fig. 8.

As can be seen from Tables 4 and 5, the feedback values of Experimental Example 3 and Comparative Example 3 were substantially negatively correlated with the hematocrit ratio in the whole blood sample. Same as The blood cell volume ratio of Experiment 3 is quite consistent for the feedback values of different relative humidity. Taking the sample having a hematocrit ratio of 21% as an example, the maximum difference of the feedback values of the experimental examples 3 for the relative humidity of 31%, 60%, and 90% was only 29.5. In contrast, Comparative Example 3 has a large variation in feedback values for different relative humidity in terms of the same hematocrit ratio. Taking a sample having a hematocrit ratio of 21% as an example, the maximum difference of the feedback values of Comparative Example 3 for relative humidity of 31%, 60%, and 90% was 173.8. Therefore, it can be seen from the above Experimental Example 3 and Comparative Example 3 that the embodiment of the present invention applies a voltage detection to a whole blood sample by square wave voltammetry, and estimates the blood cell volume ratio by taking the feedback value after the first group. Avoid the effects of moisture in the environment on its results.

In summary, the method for measuring the hematocrit ratio of the embodiment of the present invention applies a square wave to the first electrode of the test strip by square wave voltammetry after the whole blood sample stays in the first reaction zone for an interval time. The voltage or the continuous application of multiple sets of square wave voltages to the first electrode by square wave voltammetry can effectively destroy the water film and microbubbles between the whole blood sample and the electrode. In this way, the influence of moisture and microbubbles in the environment on the measurement of the hematocrit ratio can be reduced, so that a more accurate hematocrit ratio can be measured. In addition, the present invention uses the square wave voltammetry to measure the hematocrit ratio, which is less susceptible to the target analyte concentration.

The blood detecting method according to the embodiment of the present invention estimates the concentration of the target analyte in the whole blood sample based on the measured blood cell volume ratio and another feedback value obtained by applying a voltage to the second electrode. In some embodiments, it is determined whether the concentration of the target analyte derived from the feedback value is used by determining whether the ratio of the feedback values of the two sets of square wave voltages is within a specific range. Applying multiple sets of square wave voltages continuously In the embodiment, it is determined whether or not the ratio of the arbitrary two feedback values of the square wave voltage after the first group is within a specific range, and whether or not the concentration of the target analyte estimated by the feedback value is used. In this way, the blood detecting method of the embodiment of the present invention can eliminate the interference caused by external factors on detecting the concentration of the target analyte.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

Claims (5)

A method for measuring a blood cell volume ratio, comprising: providing a test strip, wherein the test strip includes a reaction zone and a pair of electrodes disposed in the reaction zone; allowing a whole blood sample to enter the reaction zone; After the whole blood sample enters the reaction zone, a set of square wave voltages are applied to the pair of electrodes by square wave voltammetry to obtain a feedback value associated with the hematocrit ratio, wherein the whole blood sample enters the reaction The start time point of the zone is different from the start time point of applying the set of square wave voltages by 0.1 second to 200 seconds; and the blood cell volume ratio is calculated according to the feedback value, wherein the method for estimating the blood cell volume ratio comprises: Generating a feedback value for a hematocrit ratio by using a standard whole blood sample of a known hematocrit ratio; and substituting the feedback value of the whole blood sample into the feedback value of the formula to obtain a corresponding blood cell The value of the volume ratio. The method for measuring a hematocrit ratio according to the first aspect of the invention, wherein the pair of electrodes comprises a working electrode and a reference electrode, and the distance between the working electrode and the reference electrode ranges from 0.01 mm to 5 mm, and / The ratio of the area of the working electrode to the area of the reference electrode ranges from 1 to 1.5. The method for measuring a hematocrit ratio according to claim 1, wherein the set of square wave voltages has a frequency ranging from 100 Hz to 4000 Hz, the group The amplitude of the square wave voltage is greater than or equal to 0.01 V, and/or the voltage increase in the set of square wave voltages ranges from 0.01 V to 0.4 V. The method for measuring a hematocrit ratio according to claim 1, wherein the voltage sweep range of the set of square wave voltages is 0V to 0.8V, and/or the application time range of the set of square wave voltages. It is 0.01 seconds to 4 seconds. A method for measuring a blood cell volume ratio, comprising: providing a test strip, wherein the test strip includes a reaction zone and a pair of electrodes disposed in the reaction zone; allowing a whole blood sample to enter the reaction zone; Voltammetry continuously applies a plurality of sets of square wave voltages to the pair of electrodes to obtain a plurality of feedback values related to a hematocrit ratio, wherein an interval between adjacent two groups of square wave voltages is 0.1 second to 4 seconds; The feedback value of the group square wave voltage is used to derive the hematocrit ratio of the whole blood sample, where n is a positive integer greater than one.