KR100967621B1 - The method for reducing measurement error using kinetic changing information and the apparatus thereof - Google Patents

The method for reducing measurement error using kinetic changing information and the apparatus thereof Download PDF

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KR100967621B1
KR100967621B1 KR1020080006627A KR20080006627A KR100967621B1 KR 100967621 B1 KR100967621 B1 KR 100967621B1 KR 1020080006627 A KR1020080006627 A KR 1020080006627A KR 20080006627 A KR20080006627 A KR 20080006627A KR 100967621 B1 KR100967621 B1 KR 100967621B1
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material
error
change information
value
kinetic
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KR1020080006627A
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KR20090080716A (en
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원용관
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전남대학교산학협력단
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Abstract

The present invention relates to an error correction method and apparatus using kinetic change information of a measurement target, and more specifically, kinetic change information on characteristics (concentration, content or content, etc.) of a first substance, Using the correlation between the kinetic change information and the feature value of the second material and the correlation between the feature value of the second material and the measurement error for the feature of the first material, the feature value of the first material It relates to an error correction method and apparatus for correcting the error. To this end, the present invention includes the steps of obtaining kinetic change information on the characteristics of the first material; Estimating a feature value of a second material using the kinetic change information and a predetermined first function; Obtaining an estimation error for the feature value of the first material using the feature value of the second material and a predetermined second function; And correcting a measurement error for the feature of the first object by subtracting or estimating an error of the feature value of the first material from the measured feature value of the first material including the interference of the second material. It provides a method for correcting the measurement error using the kinetic change information, characterized in that it comprises.
Kinetic, correlation function, error correction, blood sugar, hematocrit

Description

The method for reducing measurement error using kinetic changing information and the apparatus

The present invention relates to an error correction method and apparatus using kinetic change information in an optical or electrochemical measurement of a result of a chemical reaction, and more particularly, kinetic change information on a characteristic value of a first material. An error for correcting the feature value of the first material using the correlation between kinetic change information and the feature value of the second material and the correlation between the feature value of the second material and the measurement error of the first material A calibration method and apparatus.

When measuring the content of the target substance to be measured among the mixed materials with the optical method or the electrochemical method, the result of the optical or electrochemical reaction in response to the target material is measured. Unfortunately, there is one or more other substances (hereinafter referred to as "interfering substances") that interfere with the measurement of the target substance.

These interferences caused by interference materials cause a measurement error on the target material, which is a major cause of deterioration of the performance and reliability of the product. To overcome this, conventional methods use a method of pre-removing the interference material by chemical treatment. In order to eliminate the effects of interfering materials in the application or ex post, we have focused on the measurement of the target material and obtaining separate measurements in real time. This is due to the limitations of the technology, which makes the measurement process inaccurate, complicated and expensive. There is a problem.

That is, most of the prior arts have focused on eliminating measurement errors by improving experimental and measurement processes. These techniques are complicated by the process of eliminating the measurement error by reducing the error by improving the quality of the various materials involved in the measurement process, the process of manufacturing the product performing the process is complicated to increase the price of the product There is a problem.

As a prior art, Korean Patent Application No. 1989-0014308 (October 5, 1989 filed) discloses a measurement error compensation method and a light source control circuit of a blood glucose meter.

The prior art has a measurement error detection routine for emitting light to an undiscolored blood glucose test paper for measuring blood glucose concentration and detecting a measurement error with reflected light, a value of reflected light of the blood glucose test paper discolored according to blood glucose concentration, and the measurement error detection. Although a measurement error compensation method of a blood glucose meter which calculates and compensates a measurement error detected by a routine is disclosed, a separate measurement error must be detected in real time using a measurement error detection routine in order to correct an error. It does not disclose a method of correcting an error using a temporal change of a measured value. In addition, the prior art has an object to reduce the error caused by the color difference of the blood glucose test paper.

As a prior art, Korean Patent Application No. 2006-0025890 (filed March 21, 2006) discloses "a test strip for an electrochemical biosensor that can effectively compensate for volumetric interference of red blood cells."

The technique provides a method of compensating for a conventional signal reduction by using an electrical signal obtained from a substance inside a red blood cell that determines the hematocrit, and constitutes a separate electrode and reacts with blood cells in a physiological sample to correspond to the concentration of blood cells. It includes a blood cell interference compensator for generating a method to compensate for the existing signal reduction by using the electrical signal obtained from the material inside the red blood cells. However, this technique involves complicated manufacturing and measurement processes, including a complicated electrode structure and a separate correction agent, and does not disclose error correction using the temporal change characteristic of the measured value.

As prior art, U.S. Pat. This publication introduces a non-conductive material into the electrode system to reduce the interference effect on the red blood cell volume ratio.The method of manufacturing a carbon paste electrode system using screen printing technology and a reagent / blood separation layer immobilized on the electrode system surface are disclosed. Is described. This prior art also includes the structure of the electrode and the application of a separate material, and does not include the technique of error correction based on the change in kinetic indicating the temporal change of the measured value.

Commercialized products using thin-film electrochemical enzyme electrodes in the prior art include YSI 2300 STAT PLUS (Yellow Spring Instrument, Inc.), which has three types of electrodes: enzyme thin film, outer thin film and inner thin film. It is to prepare the enzyme material reacting with the thin film type, and to produce and combine the functional polymer thin film inside and outside the thin film, respectively, to effectively block the adsorption of electrode such as red blood cells and protein. Thin-film enzyme electrodes can innovatively eliminate the hematocrit interference effect, but the introduction of three thin films into the electrode system involves a complicated process and high cost, high blood consumption and long reaction response time. This prior art also uses an enzyme electrode to reduce the error and does not include an error correction technique based on the kinetic change of the measurement target material.

As a prior art, Korean Application No. 2006-7003547 (name of the invention: an electrochemical property analysis method and analysis apparatus, and an application date: February 21, 2006) is used to analyze analyte species more accurately in order to more accurately evaluate analyte species. A technique for calibrating an analyte-dependent signal using independent signal information, wherein an analyte that is not calibrated based on the observed analyte-independent potential attenuation is calibrated by calibrating the dependent signal. To form a dependency signal. A low level or current sufficient to cause oxidation or reduction of the analyte or mediator is generated between the two cell electrodes, thereby forming a gradient of the chemical potential of the analyte or mediator between the two electrodes. After the slope is generated, analyte-independent signal is obtained from the relaxation of the chemical potential slope that would be generated by stopping the applied potential or current, and the analyte-independent signal is applied to apply the potential or current. It is used to calibrate the analyte-dependent signal obtained. The prior art uses a signal obtained in a state where a potential is supplied and a state in which a potential is not supplied, and does not include an error correction technique using kinetic change information obtained in a state where a potential is supplied.

In the prior art, Korean Application No. 2003-0036804 (name of the invention: electrochemical biosensor, filed date: June 09, 2003) reduces hematocrit by reducing the dependence of hematocrit difference of blood. The present invention relates to a sensitized membrane composition and a biosensor including the same, which can reduce the measurement error according to the amount thereof. It does not include the technique of error correction using the change of kinetic which shows the temporal change of.

In order to solve the above problems, the present invention does not use a separate complex chemical treatment to reduce the measurement error through the pre-removal of the interfering material and a method using a special structure therefor, and to the kinetic signal of the measurement target It is an object of the present invention to provide a method and apparatus for eliminating an error in a measured value of a target material by post-correction of the influence of an interference material on the measurement of a target material using a signal processing method.

In addition, the present invention does not add a separate measurement process for removing the error by using a separate additional manufacturing process and a special structure of the involved device in order to eliminate the error caused by the interference material, and the existing measurement process and structure It is an object of the present invention to provide a simple and highly efficient error elimination method and apparatus for maintaining but simply acquiring a kinetic change signal and then eliminating an error on a measured value of a target substance by using a pre-made function.

In order to achieve the above object, the present invention comprises the steps of obtaining the kinetic change information appearing over time in the measurement of the characteristic value for the first material; Estimating a feature value of a second material using the kinetic change information and a predetermined first function; Obtaining an estimation error for the feature value of the first material using the feature value of the second material and a predetermined second function; And correcting the characteristic value of the first material measured without considering the interference phenomenon of the second material by using the estimation error of the first material. Provide an error correction method.

The first function represents a correlation between the characteristic value of the second material and the kinetic change information over time, and the second function is related to the characteristic value of the second material and the measurement error of the first material. It is characterized by indicating the correlation of.

In addition, to achieve the above object, the present invention provides a kinetic information acquisition unit for obtaining kinetic change information on the feature value of the first material; A feature value estimator for estimating feature values of a second material using the kinetic change information and a predetermined first function; An estimation error acquisition unit obtaining an estimation error for the feature value of the first material by using the feature value of the second material and a predetermined second function; And a feature value correction unit for correcting a feature value of the first material measured without considering the interference phenomenon of the second material by using the estimation error of the first material. It provides an error correction device using.

In one embodiment, the error correction device includes a blood glucose measurement device, wherein the first substance is glucose (blood sugar) included in blood, and the second substance is red blood cells included in the blood, and the characteristics of the second substance The value represents hematocrit as a concentration, and the kinetic change information is characterized by change in time of the measured value in measuring the glucose concentration.

In other words, if you want to measure the amount or concentration of blood glucose in the blood by optical or electrochemical method, the measurement is interrupted by the red blood cells in the blood. Even if the blood has the same blood glucose value, blood glucose is measured according to the hematocrit. An error that results in a different value will occur. At this time, the kinetic change information representing the temporal change in blood glucose measurement is represented by a kinetic curve, and the correlation function between the hematocrit and the blood glucose measurement error obtained by estimating the hematocrit from the kinetic change information and separately obtained from the estimated hematocrit value The apparatus estimates an error by using and corrects the error by reflecting the estimated error in the finally obtained blood glucose value.

In addition, to achieve the above object, the present invention provides a computer readable recording medium having recorded thereon a computer program for executing some or all of the above methods.

Error correction method and apparatus using kinetic change information according to the present invention is not a method of reducing the measurement error through the pre-removal method of the interference material using a complex process and the structure of the device, the interference material is measured the characteristic value of the target material By post-correcting the effect on the signal processing method using a software program, there is an advantage of efficiently removing the error of the measurement value of the target material.

In addition, the error correction method and apparatus using the kinetic change information according to the present invention does not add additional chemicals, modify the structure of the device and components or separate measurement for removing the error using a separate process, After acquiring kinetic change information easily in the process of measuring the characteristic value of the target substance, there is an advantage of simply and very efficiently eliminating the error of the measured value of the target substance using a pre-made function.

That is, the error correction method and apparatus according to the present invention do not require a preliminary procedure for removing an interference substance, and do not need to improve or add a chemical addition or a medium required for a measurement process in order to minimize the interference phenomenon. By avoiding hardware reinforcement to improve precision and processing by software, it is possible to reduce the price of measuring equipment and secure the competitiveness of the product, and also to change the software program without changing chemicals, media or equipment in existing products. It is possible to easily apply the subject innovation technology only by changing.

The terminology used in the present invention is a general term that is currently widely used as possible, but in certain cases, the term is arbitrarily selected by the applicant, in which case the meaning of the term is described in the detailed description of the invention. It should be understood that the present invention in terms of terms other than these terms.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which the above objects may be specifically realized. All implementations including the present invention should be included in the scope of the present invention.

Definitions of terms used in the present specification are as follows.

Kinetic (change) refers to the change of optical color or the change of electrochemical current or voltage over time in the method of measuring a specific chemical in a sample by optical or electrochemical method.

The characteristic value is a value obtained by quantifying desired information about a target substance. In the present invention, the characteristic value refers to a concentration, content or content ratio of a specific substance.

The target substance is a substance finally to be measured, for example, blood glucose (glucose) in the blood.

An interference substance is a substance that provides a cause of causing an error by interfering with the measurement of the characteristic value in the process of measuring the characteristic value of the target substance, for example, red blood cells in the blood causing interference in blood glucose measurement.

1 is a graph showing a kinetic curve according to an embodiment of the present invention.

When measuring the concentration, content, or content ratio (hereinafter referred to as "characteristic value") of a target substance in a mixture of chemicals by using an optical method, the result of reacting with the target substance is measured as a change in intensity of color. The change in color is gradually changed in intensity over time, and the characteristic value of the target substance is calculated based on the final measured intensity of the color after a certain time or at a time when a specific condition is satisfied.

 In the case of measuring the characteristic value of a target substance in a mixture of chemicals using an electrochemical method, the result of reacting with the target substance is measured by the change of electric current or voltage, which is an electrical signal. As a result, the signal gradually changes, and the characteristic value of the target material is calculated based on the value of the finally measured electrical signal after a predetermined time or when a specific condition is satisfied.

Optical or electrical measurements of two or more chemicals that interact with each other are called kinetic, and the change over time of the measurement is called kinetic change. Ticks are often used the same as kinetic changes. The kinetic change may be represented by a kinetic curve as shown in FIG. 1. Kinetics are sometimes referred to as reflectance (% R). Kinetics according to the present invention are not limited to optical or electrical measurements, but also include measurements using other methods that satisfy the above definition.

As shown in FIG. 1, generally the measured value of the target substance included in the mixture decreases with time in various forms, ie with various kinetic changes. The kinetic change is affected by the characteristic values of the interfering substances contained in the mixture. For example, if the feature value of the interference material is large, the kinetic change may be slow, and if the feature value of the interference material is small, the kinetic change may appear suddenly. The present invention estimates the characteristic value of the interfering material by using the kinetic change having a different shape according to the characteristic value of the interfering material, and uses the correlation between the characteristic value of the interfering material and the error of the target material. The present invention relates to a method for correcting a measurement error for a characteristic value of a material.

FIG. 2 is a graph illustrating a correlation between a concentration of an interference material and a measurement error with respect to a feature value of a target material, according to an exemplary embodiment.

The magnitude of the measurement error due to the interference of the interfering material depends on the characteristic value of the interfering material, and appears to be additive or decremented with respect to the exact measurement value of the target material with the influence of the interfering material removed. That is, there is a correlation between the characteristic value of the interference material and the magnitude of the measurement error, and FIG. 2 is one embodiment illustrating the correlation.

Referring to FIG. 2, when the characteristic value of the interfering substance (represented by "concentration" in FIG. 2) is small, the measurement error with respect to the characteristic value of the target substance has a positive value (additive error). If the feature value is large, the measurement error has a negative value (reduced error). Here, the measurement error represents a difference between the characteristic value of the target substance measured using the mixture containing the interference substance and the characteristic value of the target substance measured in the state not containing the interference substance. The error distribution according to the concentration of the interference material shown in FIG. 2 is exemplary, and the present invention includes the error distribution according to the concentration of the interference material having a tendency different from that shown in FIG.

Therefore, the correlation between the characteristic value of the interfering substance and the measurement error of the target substance may be expressed by mathematical or logical rules, and if the characteristic value of the interfering substance is known, the measurement of the target substance using the correlation may be performed. An error may be obtained and the characteristic value of the target material including the error may be corrected by the interference material using the measurement error.

3 is a block diagram illustrating an error elimination apparatus using kinetic change information according to an embodiment of the present invention. Referring to FIG. 3, the error elimination apparatus includes a kinetic information acquisition unit 310, a feature value estimation unit 320, an estimation error acquisition unit 330, and a feature value correction unit 340.

The kinetic information acquisition unit 310 obtains the kinetic in the process of measuring the target substance, and obtains the change over time of the kinetic (hereinafter referred to as "kinetic change") information.

The feature value estimator 320 estimates a feature value of the interference material by using the kinetic change information and a predetermined first function (a function expressed by “g”). The first function g determined by a separate method may be included in the error correction apparatus as a function that mathematically or logically represents a correlation between the kinetic curve and the feature value.

The estimation error acquisition unit 330 obtains an estimation error of the target material by using the estimated feature value of the interference material and a predetermined second function (a function expressed by “f”). The second function f represents a correlation between the characteristic value of the interference material and the estimated error of the target material, and may be predetermined and included in the error correction apparatus by using a mathematical or logical method.

The correlation functions f and g used to correct the measurement error of the target material due to the interference of the interfering material according to the present invention can vary widely, and one embodiment of the method for obtaining the functions f and g An example will be described later.

The feature value correction unit 340 corrects the feature value of the target material obtained without considering the influence of interference of the interference material by using the estimation error of the target material obtained by the estimation error acquisition unit 330. .

Hereinafter, the error correction according to the present invention performed by the kinetic information acquisition unit 310, the feature value estimator 320, the estimated error acquisition unit 330, and the feature value correction unit 340 included in the error correction apparatus. Describe the method.

4 is a flowchart illustrating a method of removing an error using kinetic change information according to an embodiment of the present invention.

As described above, the kinetic change information can be used to estimate the feature value of the interfering material, and the target measured in the environment including the exact characteristic value of the target material measured in the environment from which the interference is removed and the interference phenomenon. If the correlation between the feature value of the material and the feature value of the interfering material is known, the correlation can be used to estimate the measurement error of the target material, and the estimated error is measured in an environment that includes the interference phenomenon. Reflecting on the characteristic value of a target material, a characteristic value without interference can be obtained.

In order to describe more clearly, the error correction method according to the present invention is expressed as follows. Here, the symbol ≒ is a symbol indicating that the values of the left and right sides are similar, and the definitions of the functions and values used are as follows.

If the exact characteristic value of the target substance without an error is T and the measured characteristic value of the target substance with an error is M, the error D = M-T is defined. If the kinetic curve (or kinetic change information) is K and the characteristic value of the interfering substance is d, the first function g representing the correlation between the characteristic value of the interfering substance and the kinetic curve is d = g (K) The second function f representing the correlation between the characteristic value of the interference material and the measurement error of the target material is represented by D = f (d).

Therefore, the characteristic value of the interference material estimated from the kinetic change information obtained from the newly supplied sample is defined as d '= g (K), and the estimation error D' = f (d ') = f {g of the target material. (K)} ≒ D, and the corrected characteristic value C = M-D '≒ M-D = T of the target substance can be obtained.

That is, the correlation function g (K) between the characteristic value of the interference material and the kinetic curve and the correlation function f (d) between the characteristic value of the interference material and the measurement error of the target material are previously determined by a mathematical or logical rule. If known, an estimate (d ') of the characteristic value of the interfering substance can be calculated for the target substance present in the newly supplied sample, and an estimation error (D') can be calculated based on this. By subtracting the estimated error D 'from the measured value M including, a value close to the exact feature value T can be obtained.

Hereinafter, the error elimination method will be described with reference to a flowchart of the error correction apparatus shown in FIG. 3 and the error elimination method shown in FIG. 4. First, the kinetic information acquisition unit 310 obtains kinetic change information on a target substance (hereinafter, referred to as a "first substance") to be measured (S410). The kinetic change information is information in which a characteristic value of a material to be measured changes with time, and is represented by a kinetic curve.

The feature value estimator 320 is then characterized by the kinetic change information obtained in the measurement of the first substance and the characteristic value d 'of the interfering substance (hereinafter referred to as " second substance ") using the predetermined first function g. Estimate (S420).

Subsequently, the estimation error acquisition unit 330 obtains an estimation error corresponding to the feature value of the first material by using the feature value of the second material and the predetermined second function f (S430). The government 340 corrects the measured feature value for the first material using the estimation error (S440).

There are various ways to obtain the two correlation functions, the first function g and the second function f, and any function that minimizes E g and E f defined in Equations 1 and 2, respectively, is possible. Do.

Figure 112008005277069-pat00001

Where i is the index representing each mixture sample, d (i) is the characteristic value of the second material accurately measured, and d '(i) = g {K (i)} uses kinetic change information. Is the characteristic value of the second material estimated by the first function g, ie E g represents the accumulation of the error for the second material)

Figure 112008005277069-pat00002

(Where i is an index representing each mixture sample, D (i) is the exact measurement error for the first substance generated by the measuring instrument, and f {d '(i)} is based on kinetic change information) Is an estimation error of the first substance obtained by using the second function f and the estimated value d 'of the second substance using the first function g, that is, E f is the first value defined as the difference between the exact value and the estimated value. Cumulative error for the material).

The two equations are expressed as a cumulative difference between the exact value and the estimated value (hereinafter, referred to as the “total error”) for a large number of samples, and the first and second functions minimize It becomes a satisfying function. Functions for minimizing these may vary depending on the mathematical or logical method for obtaining them, so that a difference in the absolute minimum of E g and E f may occur. That is, the precision of the error correction may vary depending on how the two functions are obtained. The present invention includes both methods for correcting an error using such a function, regardless of how two functions are obtained.

As described above, the feature of the error correction method according to the present invention is (1) the first function g (K) representing the correlation between the kinetic change and the second material feature value from a large number of previously obtained measurement data. (2) also obtains a function f (d) representing the correlation between the characteristic value for the second substance and the estimated error value of the first substance from a large number of previously obtained measurement data. If a measurement request for the characteristic value of the first material is generated, K is secured in the process of measuring the characteristic value, and the characteristic value d 'of the second material is estimated by the function g (K), and (4) the estimated second Obtain the estimation error D '= f (d') of the first substance by the characteristic value d 'of the substance and the second function f, and (5) estimate it from the characteristic value M of the first substance measured without considering the interference phenomenon. Subtract the value of the error f (d ') to find the characteristic value C of the first substance which corrects the error due to the interference phenomenon. Consists of a series of processes, in which two correlation functions g (K) and f (x) are used. Hereinafter, an embodiment using the error correction method and apparatus according to the present invention for measuring blood glucose will be described.

In order to express the above-mentioned contents more clearly, it is expressed as follows. At this time, the symbol ≒ is a symbol indicating that the values of the left and right sides are similar.

* Exact value T, target substance (first substance) measurement M with error, interference error D:

M = T + D or T = M-D

Kinetic curve: K

* Characteristic value of the interference material (second material): d

* The correlation function g between the interfering substance (secondary substance) characteristic and the kinetic curve:

d = g (K)

* A correlation function f between the interfering substance (second substance) characteristic and the interference value (error) f:

D = f (d)

* Characteristic estimate d 'of the target substance (first substance) for the new sample:

d '= g (K)

* Estimation error D ': D' = f (d ') = f {g (K)} ≒ D

* Correction value C: C = M-D '≒ M-D = T

In other words, if the correlation function g (K) between the characteristic of the interference material and the kinetic curve and the correlation function f (d) between the characteristic of the interference material and the error value are known in advance by mathematical or logical rules, The estimated value d 'of the characteristic value of the interfering substance can be calculated for the measurement object, and the estimated error D' can be obtained based on this, and the estimated error in the measured value M including the error caused by the interference phenomenon. By subtracting (D '), a value close to the exact value (T) can be obtained.

5 is a graph showing a relationship between kinetic change information and the concentration of hematocrit contained in blood according to an embodiment of the present invention.

When blood glucose (or glucose) concentration in the blood is to be measured by a blood glucose sensor and a portable blood glucose meter, red blood cells act as an interfering substance, and thus an error in the measured blood glucose value varies according to hematocrit. However, the kinetic change information of the blood glucose measurement is different depending on the concentration of the red blood cells contained in the blood. Referring to FIG. 5, when the concentration of hematocrit is 20%, the concentration of blood sugar gradually decreases with time, and when the concentration of hematocrit is 60%, the concentration of blood sugar rapidly decreases with time. Therefore, even if two blood samples having the same blood sugar value, the blood glucose value measured at a certain time may be different, and on the contrary, two blood samples having different blood sugar values may be measured with the same blood sugar value.

By using the correlation between the concentration of hematocrit and the kinetic change information for blood sugar, the hematocrit concentration representing the volume ratio of red blood cells in the blood can be estimated from the kinetic change information of blood sugar. By using the relationship between the estimated hematocrit concentration and the error of the blood glucose measurement value, the error included in the blood glucose measurement value can be removed.

In other words, when measuring blood glucose levels of whole blood using a blood glucose sensor and a portable self-glucometer that do not completely remove the effects of hematocrit, an expensive fine chemical analyzer that can remove the effect of hematocrit (for example, For example, an error due to interference of hematocrit is added to the value measured by the YSI2300 to be measured.

In this case, the prior art focused on improving the quality and performance of the blood glucose sensor used as a medium of measurement in order to minimize the effect of hematocrit, but when the present invention is applied, the blood glucose measurement error is corrected by applying a simple numerical analysis method. It can be implemented by a new blood glucose measurement device, or by adding a function for correcting the interference of hematocrit in blood glucose measurement using a conventional portable device.

Hereinafter, in order to prove the effect of error correction on the blood glucose measurement by applying the technique of the present invention, the results of performing a comparative experiment with a commercial product using the same blood glucose sensor will be described.

First, a description of the drawings showing the results related to the present experiment. 6 shows hematocrit precision (d), blood glucose precision (T) by YSI2300, hematocrit estimate (d ') and corrected blood glucose value estimate (C) for whole blood sample samples, It is a table including the error value of the estimated values, the measurement value of the commercial product blood glucose apparatus using the same blood glucose sensor and the error value thereof, Figure 7 is a graph showing the interference phenomenon caused by the concentration of hematocrit in blood glucose measurement, Low concentrations lead to positive errors and high concentrations to cause negative errors. (Based on Richard F. Louie et al , “Point-of-Care Glucose Testing: Effects of Critical Care Variables, Influence of Reference Instruments, and a Modular Glucose Meter Design”, Arch. Pathol. Lab. Med, Vol. 124, February 2000)

 8 is a graph of (a) error distribution and (b) normalized error distribution for each concentration of hematocrit according to an embodiment of the present invention and the existing commercial product, and FIG. 9 is a reference device for each blood sample, YSI2300. This is a graph showing the exact blood glucose value ('actual value' on the X-axis), the measured value by the portable type, and the blood glucose calculated value (the 'measured value' on the Y-axis) according to the method of the present invention. No error is shown for. That is, the closer it is to the right diagonal line, the better the measurement result.

The experiment for comparison is as follows. First, 27 randomly selected combinations of low, medium and high cases of hematocrit and blood glucose values were randomly selected from a number of random patients, and the following four values were measured for each of their blood: .

The first value is the hematocrit concentration in the blood as measured by the hematocrit precision measuring instrument used in the clinical laboratory of the hospital.

The second value is a blood glucose value measured using a precision measuring device (YSI2300) used as a reference device for blood glucose measurement.

The third value is the blood glucose value measured in the blood using a commercially available product (ie, a blood glucose sensor and a matching device) that is already on the market. At this time, in order to eliminate the problem of reproducibility caused by the poor blood glucose sensor itself, the value of the measuring instrument is taken as the middle value among the values obtained through the three measurements. In other words, in this comparison experiment, three sensors were measured to minimize the reproducibility problem of the blood glucose sensor itself, and only three cases were similar within a certain range. The measurement result in the middle case was selected.

The fourth value is change information of kinetic collected from the measuring instrument in the process of measuring the third value using a conventional measuring instrument. Kinetic information was measured every 0.5 seconds and a total of 13 seconds were measured.

The three measured values (YSI2300 measured value, hematocrit concentration, commercial product measured value), hematocrit estimates and blood glucose estimates according to the method according to the present invention, and their error values are shown in the table shown in FIG. 6, the root-mean-squared-error (RMSE) for the blood sugar estimated value and the conventional commercial product measured values are 5.32476 and 8.9148, and the error in calculating the blood sugar value by the method according to the present invention is generally known. It shows less error than used product.

FIG. 8 (a) shows the error of blood glucose measurement by the method according to the present invention and the conventional product for each concentration of hematocrit with respect to the table shown in FIG. 6, and the method according to the present invention has a negative error distribution. Although not biased with negative or positive values, conventional products tend to appear negative. FIG. 8 (b) shows a result of normalizing the result illustrated in FIG. 8 (a) to be based on an average value of errors in order to remove a negative or positive trend. As shown in (a) and (b) of FIG. 8, the estimated values of blood glucose and the measured values of conventional products by the method according to the present invention are negative or positive shown in FIGS. 2 and 7. It can be seen that the error occurrence phenomenon has been eliminated, and the error by the method of the present invention is less, thereby demonstrating the effectiveness of the method devised in the present invention.

FIG. 9 is a diagram illustrating another example of the error distribution shown in FIG. 8 and the table shown in FIG. 6. In the figure, the upward diagonal indicates that the measured value (Y-axis) is the same as the precise measured value (X-axis), and when positioned on the diagonal upward, there is no error for the blood sample. That is, the higher the diagonal on the right side, the better the measurement result. The blood glucose value estimated by the method devised in the present invention is closer to the diagonal upward upward than the existing commercial product, which is one experimental result that demonstrates the effectiveness of the method of the present invention.

As can be seen from the above comparative experiments, the method according to the present invention for estimating the hematocrit from kinetic change information and correcting the error of the measuring instrument based on the kinetic change information can improve the performance by reducing the measurement error of conventional commercial products. have.

In the present invention as described above has been described by the limited embodiment and the drawings, but this is provided only to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, it is common in the field of the present invention Those skilled in the art can make various modifications and variations from this description.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later will belong to the scope of the present invention. .

1 is a graph showing a kinetic curve according to an embodiment of the present invention.

2 is a graph showing the correlation between the concentration of the interference material and the measurement error for the characteristic value of the target material according to an embodiment of the present invention.

3 is a functional block diagram of an error cancellation apparatus using kinetic change information according to an embodiment of the present invention.

4 is a flowchart illustrating an error elimination method using kinetic change information according to an embodiment of the present invention.

5 is a graph showing the relationship between kinetic change information and hematocrit concentration in blood according to an embodiment of the present invention.

6 is a table showing hematocrit estimates, blood sugar estimates, and error values of the estimates in accordance with one embodiment of the present invention.

Figure 7 is a graph showing a positive or negative error distribution tendency for each concentration of hematocrit according to an embodiment of the present invention.

8 is a graph showing the error distribution and normalized error distribution for each hematocrit concentration according to an embodiment of the present invention.

Figure 9 is a graph comparing the error distribution of the error distribution and the conventional method according to an embodiment of the present invention.

Claims (13)

  1. Obtaining kinetic change information for the feature value of the first material;
    Estimating a feature value of a second material using the kinetic change information and a predetermined first function;
    Obtaining an estimation error for the feature value of the first material using the feature value of the second material and a predetermined second function; And
    And correcting a characteristic value of the first material measured without considering the interference phenomenon of the second material by using the estimation error of the first material.
    The kinetic change information means the error correction method using kinetic change information, characterized in that the change over time of the feature value for the material to be measured.
  2. The method of claim 1,
    And the first function indicates a correlation between a feature value of the second material and the kinetic change information.
  3. The method of claim 2,
    The first function is E g defined by Equation 1 below. Error correction method using kinetic change information characterized by minimizing the value.
    &Quot; (1) "
    Figure 112008005277069-pat00003
    Where i is the index representing each mixture sample, d (i) is the characteristic value of the second material accurately measured, and d '(i) = g {K (i)} uses kinetic change information. Is the characteristic value of the second material estimated by the first function g, ie E g represents the accumulation of the error for the second material)
  4. The method of claim 1,
    The second function is error correction method using the kinetic change information, characterized in that the correlation between the characteristic value of the second material and the measurement error of the first material.
  5. The method of claim 4, wherein
    And the second function minimizes an E f value defined by Equation 2 below.
    <Equation 2>
    Figure 112008005277069-pat00004
    (Where i is an index representing each mixture sample, D (i) is the exact measurement error for the first substance generated by the measuring instrument, and f {d '(i)} is based on kinetic change information) Is an estimation error of the first substance obtained by using the second function f and the estimated value d 'of the second substance using the first function g, that is, E f is a first Indicates an accumulation of errors for a substance)
  6.  6. The method according to any one of claims 1 to 5,
    The first substance is glucose (blood sugar) contained in blood, and the second substance is error correction method using kinetic change information, characterized in that the red blood cells contained in the blood.
  7. The method of claim 6,
    The characteristic value is a concentration, and the kinetic change information is error correction method using kinetic change information, characterized in that the measurement value for the glucose concentration changes over time.
  8. A kinetic information acquisition unit for acquiring kinetic change information on the feature value of the first material;
    A feature value estimator for estimating feature values of a second material using the kinetic change information and a predetermined first function;
    An estimation error acquisition unit obtaining an estimation error for the feature value of the first material by using the feature value of the second material and a predetermined second function; And
    A kinetic change information comprising: a characteristic value correction unit for correcting a characteristic value of the first material measured without considering the interference phenomenon of the second material by using the estimation error of the first material Error correction device used.
  9. The method of claim 8,
    The first function is error correction apparatus using the kinetic change information, characterized in that the correlation between the characteristic value of the second material and the kinetic change information.
  10. The method of claim 8,
    The second function is error correction apparatus using kinetic change information, characterized in that the correlation between the characteristic value of the second material and the measurement error of the first material.
  11. The method according to any one of claims 8 to 10,
    The first substance is glucose (blood sugar) contained in the blood, and the second substance is error correction apparatus using kinetic change information, characterized in that the red blood cells contained in the blood.
  12. The method of claim 11,
    The feature value is a concentration, and the kinetic change information is error correction apparatus using kinetic change information, characterized in that the measurement value for the glucose concentration changes over time.
  13. A computer-readable recording medium having recorded thereon a computer program for executing the method according to any one of claims 1 to 5.
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US12/863,985 US8725427B2 (en) 2008-01-22 2009-01-21 Method and apparatus for estimating features of target materials by using kinetic change information
PCT/KR2009/000308 WO2009093840A2 (en) 2008-01-22 2009-01-21 Method and apparatus for estimating features of target materials by using kinetic change information
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020125145A1 (en) 2000-02-02 2002-09-12 Timothy Ohara Electrochemical methods and devices for use in the determination of hematocrit corrected analyte concentrations
KR20060019442A (en) * 2004-08-27 2006-03-03 주식회사 인포피아 Measurement equipment for a biosensor which measures the reaction result of a sample
US20070043281A1 (en) 2005-08-17 2007-02-22 Orsense Ltd. Method and device for non-invasive measurements of blood parameters

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020125145A1 (en) 2000-02-02 2002-09-12 Timothy Ohara Electrochemical methods and devices for use in the determination of hematocrit corrected analyte concentrations
KR20060019442A (en) * 2004-08-27 2006-03-03 주식회사 인포피아 Measurement equipment for a biosensor which measures the reaction result of a sample
US20070043281A1 (en) 2005-08-17 2007-02-22 Orsense Ltd. Method and device for non-invasive measurements of blood parameters

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논문 : Clin Biochem

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