KR102599838B1 - Lab target range setting method using pooled standard deviation - Google Patents

Abstract

The laboratory tolerance setting method using the mixed standard deviation according to an embodiment of the present invention obtains measurement values for reagents with at least two different manufacturing numbers, then performs statistical processing to obtain the average value and standard value of the measurement values. Calculating average value and standard deviation, calculating deviation; A mixing standard deviation calculation step of calculating the mixing standard deviation of the reagents; A mixed standard deviation application step of replacing the standard deviation calculated in the average value and standard deviation calculation step with the mixed standard deviation calculated in the mixed standard deviation calculation step; and a lab target registration step of registering the calculated average value and the calculated mixed standard deviation as a lab target for setting an acceptable range of the laboratory.

Description

Method for setting laboratory tolerance range using mixed standard deviation {LAB TARGET RANGE SETTING METHOD USING POOLED STANDARD DEVIATION}

The present invention relates to internal quality control of medical test data, and more specifically, to a method of setting a laboratory tolerance range using mixed standard deviation for internal quality control of medical test data.

All tests performed in the Department of Laboratory Medicine are an important part of medical practice, and it is very important to obtain reliable test results. To achieve this, accurate evaluation of inspection quality is necessary to improve inspection quality, and standardization of inspection work is also an important factor.

Quality control refers to all processes implemented to ensure that test results satisfy the needs of medical services treating patients. In other words, the test results measuring the components of the patient's blood, urine, body fluids, etc. become an important standard for diagnosis, treatment, and follow-up of the disease by objectifying the patient's symptoms and signs, so the test is performed to obtain the accuracy and reliability of the test results. Total Quality Management (TQM) must be implemented to maintain and improve quality.

Components of comprehensive quality control include quality planning (QP), quality laboratory practice (QLP), quality control (QC), quality assessment (QA), and quality improvement. Improvement, QI).

The purpose of internal quality control is to discover in advance analytical errors that may occur during testing, and analytical errors include random error and systematic error. If the test is repeated indefinitely, the measured value forms a normal distribution with a mean and standard deviation. Random error is an error where the mean is the same but the standard deviation has increased, and systematic error can be defined as an error where the standard deviation is the same but the mean has shifted. .

Statistical quality control evaluates test methods by periodically measuring quality control materials (QC materials) whose exact values are known. If the measurement result of the quality control material is within the acceptable range, it is verified that sufficient results that can be used clinically can be shown even when the sample is tested. If the measurement result of the quality control material is outside the allowable range, the test result of the sample cannot be reported, and corrective action must be taken if necessary.

If systematic errors exist, systematic errors occur in all test results, which also causes errors in quality control measurements. Statistical quality control detects systematic errors that occur during testing by comparing measured values and expectations of quality control materials using statistical techniques. Since random errors do not occur in all test results but only in some test results, there may or may not be random errors in the measured values of quality control materials. Therefore, there is a limit to detecting random errors through quality control using quality control materials. there is.

The principles of statistical quality control were used in industry, and were introduced to laboratory medicine and laboratory work by Levy and Jennings in 1950.

The three steps of general statistical quality control are 1) selection of quality control materials, 2) calculation of mean and standard deviation, and 3) application of statistical quality control system. Each step is described below.

1) Selection of quality control materials

Quality control materials are samples used for statistical quality control, and various quality control materials are commercialized. The ideal quality control material should be physically and chemically identical to the matrix of the sample to be tested. In statistical quality control, quality control substances of 2 to 3 concentrations are used to cover the important clinical judgment range of the test item. Generally, quality control substances of 2 concentrations are used in general chemistry tests, and quality control substances of 2 concentrations are used in immunochemical tests and blood tests. Three concentrations of quality control substances are used in gas testing.

2) Calculation of average and standard deviation

To apply statistical quality control, the average and standard deviation of quality control materials must be calculated. The above average and standard deviation must be calculated based on measurements taken over at least 20 days, and measurements determined to have errors must be excluded from the calculation. Since the average and standard deviation calculated with a small number of measurements are not accurate, it is necessary to calculate the average and standard deviation again with accumulated measurement values.

3) Application of statistical quality control system

The measured values of quality control materials are expressed visually using a control chart. Statistical quality control using quality control materials includes the Levey Jennings control chart and Westgard multirule. The Levi-Jennings control chart is a method that determines that there is an error if the measured value of the quality control material is outside the range of ±2 standard deviations from the preset average. Although it has a high error detection rate, it has the disadvantage of also having a high false rejection rate.

Meanwhile, the quality control material for a specific test item may include several reagents with different lot numbers. The batch numbers of the above reagents can be determined by the manufacturer. Since the quality of reagents with different production numbers may not be completely the same, certain differences may occur in the measurement results. If reagents with different manufacturing numbers are used, the problem of inflating the cumulative standard deviation may occur.

Specifically, in calculating the average and standard deviation of the quality control material in 2) above, when determining the standard deviation (SD) of the quality control material, if the lot number of the reagent is changed, the quality control material Changes in the measured values of quality control materials occur due to matrix-related reactions between the and the changed reagent. Because the cumulative standard deviation (SD) is inflated due to artificial fluctuations in the measured values, it is not appropriate for internal quality control. Therefore, a method that can compensate for artificial fluctuations in measured values obtained through at least two reagents with different serial numbers is required.

KR 10-2020-0111397 A (September 29, 2020)

An embodiment of the present invention provides a method for setting a laboratory tolerance range that can alleviate or compensate for artificial fluctuations due to changes in measurement values when using reagents with different production numbers as quality control materials.

The laboratory tolerance setting method using the mixed standard deviation according to an embodiment of the present invention obtains measurement values for reagents with at least two different manufacturing numbers, then performs statistical processing to obtain the average value and standard value of the measurement values. Calculating average value and standard deviation, calculating deviation; A mixing standard deviation calculation step of calculating the mixing standard deviation of the reagents; A mixed standard deviation application step of replacing the standard deviation calculated in the average value and standard deviation calculation step with the mixed standard deviation calculated in the mixed standard deviation calculation step; and a lab target registration step of registering the calculated average value and the calculated mixed standard deviation as a lab target for setting an acceptable range of the laboratory.

Here, in the step of calculating the mixed standard deviation, the measured values are classified by serial number of the reagents, then the standard deviation is calculated for each serial number, and the mixed standard deviation is calculated based on the calculated standard deviations for each serial number. It can be calculated.

Here, the mixed standard deviation can be calculated based on the standard deviations for each serial number using the following equation.

<Equation>

In the above <Equation>, SD _Pooled is the mixed standard deviation, n _k is the number of measurements of the reagent with the k (a natural number of 2 or more)th batch number, and SD _k is the standard deviation of the reagent with the kth batch number. .

Here, the mixed standard deviation can be calculated separately by concentration of the quality control substances.

Here, before the step of calculating the average value and standard deviation, a stocking and registration step in which the reagents are classified and registered by the manufacturing number may be further included.

Here, in the receipt and registration step, at least one of the reagent name, application date, manufacturer, expiration date, receipt date, equipment name, and quality control material for each batch number may be received and registered together with the batch number.

Here, in the lap target registration step, the application date and application of the lap target may be selected, and whether the mixed standard deviation may be applied may be displayed on the display screen.

Here, between the mixed standard deviation application step and the wrap target registration step, at least one test item to be applied as the wrap target is selected from among a plurality of test items to which the wrap target is applied, and only the selected test items are selected. A step of applying it as a lab target may be further included.

The recording medium according to an embodiment of the present invention may be a computer-readable recording medium for recording a computer program for executing the method for setting a laboratory tolerance range described above.

According to the method for setting a laboratory tolerance range according to an embodiment of the present invention, there is an advantage of preventing or alleviating inflation of the cumulative standard deviation due to artificial variation when reagents with different batch numbers are used as quality control materials.

Figure 1 is a flowchart of a method for setting a laboratory tolerance range using mixed standard deviation according to an embodiment of the present invention.
FIG. 2 is a display screen for explaining step S110 of FIG. 1.
FIG. 3 is a display screen for explaining steps S130 and S140 of FIG. 1.
FIG. 4 is a display screen for explaining step S150 of FIG. 1.
Figure 5 is a display screen for explaining steps S160 and S170 of Figure 1.
FIG. 6 is a display screen for explaining step S190 of FIG. 1.
Figures 7 and 8 are diagrams for explaining a method in which lap target registration is possible only for at least one specific inspection item in step S170 of Figure 1.
Figure 9 is a schematic block configuration diagram of an internal quality control device in which the laboratory tolerance range setting method using the mixed standard deviation according to the embodiment of the present invention shown in Figures 1 to 8 can be implemented.

The following merely illustrates the principles of the invention. Therefore, those skilled in the art will be able to invent various devices that embody the principles of the invention and are included in the concept and scope of the invention, although not clearly described or shown herein. In addition, all conditional terms and embodiments listed herein are, in principle, expressly intended only for the purpose of enabling the inventive concept to be understood, and are not to be construed as limiting to the embodiments and states specifically enumerated as such. do.

Additionally, it is to be understood that any detailed description reciting specific embodiments, as well as principles, aspects and embodiments of the invention, is intended to encompass structural and functional equivalents of such matters. In addition, these equivalents should be understood to include not only currently known equivalents but also equivalents developed in the future, that is, all elements invented to perform the same function regardless of structure.

In the claims of this specification, components expressed as means for performing the functions described in the detailed description include, for example, any type of software including a combination of circuit elements or firmware/microcode that performs the functions. It is intended to include any method of performing the functions included, coupled with suitable circuitry for executing the software to perform the functions. Since the invention defined by these patent claims combines the functions provided by various listed means and is combined with the method required by the claims, any means capable of providing the above functions are equivalent to those identified from the present specification. It should be understood as

When a component is said to be “connected” or “connected” to another component, it is understood that it may be directly connected or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings that can be commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless clearly specifically defined.

In this specification, singular forms may also include plural forms unless specifically stated in the phrase. As used herein, “comprises” and/or “comprising” refers to the presence of one or more other components, steps, operations and/or elements. or does not rule out addition.

The above-mentioned purpose, features and advantages will become clearer through the following detailed description in relation to the attached drawings, and accordingly, those skilled in the art in the technical field to which the invention pertains will be able to easily implement the technical idea of the invention. . Additionally, when describing the invention, if it is determined that a detailed description of known technology related to the invention may unnecessarily obscure the gist of the invention, the detailed description will be omitted. Hereinafter, a preferred embodiment according to the invention will be described in detail with reference to the attached drawings.

Hereinafter, the method of setting the laboratory tolerance range using the mixed standard deviation of the present invention is not limited to the hospital laboratory medicine department, and can be applied to all laboratories that perform tests, such as hospital laboratory medicine departments, nuclear medicine departments, and research institutes. .

Figure 1 is a flowchart of a method for setting a laboratory tolerance range using mixed standard deviation according to an embodiment of the present invention.

The laboratory tolerance setting method using the mixed standard deviation according to the embodiment of the present invention shown in FIG. 1 can be performed in an internal quality control device. The internal quality control device will be described later in Figure 9.

Referring to FIG. 1, the laboratory tolerance setting method using the mixed standard deviation according to an embodiment of the present invention includes the step of registering the receipt of reagents with at least two different lot numbers (S110). , Obtaining and storing measured values for the reagents (S120), Statistically processing the measured values to calculate the mean value (Mean) and standard deviation (SD) (S130), Mixed standard deviation (Pooled SD) A step of determining whether application is selected (S140); If application of the mixed standard deviation is selected, a step of calculating the pooled SD of the reagents (S150); and a step of applying the calculated pooled standard deviation (S160) ), a step of determining whether application of the lab target has been selected (S170), and if application of the lab target has been selected, a step of registering the calculated average value and (mixed) standard deviation as a lab target (S180). .

In step S110, the receipt of reagents with at least two different lot numbers is registered. Specifically, referring to FIG. 2, in a specific quality control material (HDL/LDL QC), at least two or more reagents with different lot numbers may exist. Reagents with different manufacturing numbers can be received and registered by being classified by at least one of the following: reagent name, application date, manufacturer, expiration date, receipt date, equipment name, and quality control material. The reagents can be registered by scanning the barcode attached to the packaging material of the reagent using a scanner connected to an internal quality control device, or by the user directly. This registered reagent receipt information can be used to calculate the standard deviation for each reagent with different manufacturing numbers in step S150.

Step S120 obtains and stores measurement values for at least two reagents with different manufacturing numbers. Here, the measured value is a value obtained by measuring the test items for the reagents using equipment in a given laboratory. Specifically, as shown in FIG. 3, the measured values are obtained by testing the reagents using equipment that can measure certain test items (HLD-cholesterol, LDL-cholesterol) in a certain laboratory. -This is a measurement of cholesterol levels. The measured values can be obtained and stored according to the number of measurements and date of measurement.

In step S130, the measured values obtained in step S120 are statistically processed to calculate the mean value (Mean) and standard deviation (SD). Here, referring to FIG. 3, the calculated average value and standard deviation may be the average value and standard deviation for all reagents with different manufacturing numbers. When using this standard deviation to set the laboratory's tolerance range, as previously explained in the [Background Technology] section, the cumulative standard deviation is inflated due to changes in measured values due to substrate-related reactions between reagents. Problems may arise.

In step S130, the internal quality control device can determine whether the measurement values for each reagent have been measured more than a predetermined number of times. If the number of measurements for each reagent is more than a predetermined value, the internal quality control device can statistically process the measured values of all reagents to calculate the mean value (MEAN) and standard deviation (SD).

Step S140 determines whether application of pooled SD is selected. Whether or not application of mixed standard deviation is selected may be determined based on the user's selection. Referring to FIG. 3, the application of mixed standard deviation can be selected by the user selecting 'Pooled SD (310)' located at the bottom of the display screen. If the mixed standard deviation is applied, step S150 is performed, otherwise step S170 is performed.

In step S150, if application of the mixed standard deviation is selected in step S140, the mixed standard deviation of the reagents is calculated.

In step S150, the standard deviation (SD) of each reagent with at least two different manufacturing numbers of the test item may be calculated, and then the mixed standard deviation (Pooled SD) of the reagents may be calculated. Referring to FIG. 4, when the user selects 'Pooled SD (310)' located at the bottom of the display screen, a pop-up window may be created where the mixed standard deviation (Pooled SD) can be viewed. In the pop-up window, the standard deviation (SD) is calculated for each reagent with different lot number for each test item (HLD-cholesterol/LDL-cholesterol). Here, the reagent manufacturing number (Lot No.), trial period, and standard deviation by concentration (SD-level1, SD-level2??) can be displayed for each reagent. This display information may be information obtained through warehousing registration in step S110.

Once the standard deviation (SD) is calculated for each reagent of the test item, the mixed standard deviation (Pooled SD) of the test item is calculated. Specifically, the mixed standard deviation (Pooled SD) of three reagents with different batch numbers for one test item, HLD-cholesterol, is calculated. Likewise, the pooled SD of two different batch numbers for another test item, LDL-cholesterol, is calculated.

In step S150, the pooled standard deviation (Pooled SD) for each test item is calculated based on the standard deviation (SD) for reagents with at least two different batch numbers of the test item. As a method of calculating the pooled standard deviation (Pooled SD), the following <Equation 1> can be used.

In <Equation 1> above, SD _Pooled is the mixed standard deviation, n _k is the number of measurements of the reagent with the k (where k is a natural number of 2 or more)th serial number, and SD _k is the number of measurements of the reagent with the kth serial number. This is the standard deviation of the reagent.

Here, the mixing standard deviation can be calculated for each concentration of reagents with different manufacturing numbers. Referring to FIG. 4, the mixed standard deviation can be calculated for each concentration of the reagent (SD-level1, SD-level2, SD-level3, SD-level4).

Step S160 is a step in which the mixed standard deviation calculated in step S150 is applied. In step S160, as shown in FIG. 4, 'Apply (410)' displayed at the bottom of the pop-up window where the mixed standard deviation (Pooled SD) can be viewed is selected by the user, and the calculated mixed standard deviation is applied. You can. When the calculated mixed standard deviation is applied, as shown in FIG. 5, the existing standard deviation (SD) displayed on the display screen is changed to displayed as a mixed standard deviation (Poolded SD, 501), and accordingly, the existing target The target range is also displayed as a pooled target range (502). Since the pooled target range (502) is changed by the pooled standard deviation (Pooled SD), the laboratory's tolerance range is re-established. There is an advantage that the cumulative standard deviation (cumulative SD) is not inflated by this changed pooled target range (502).

Step S170 determines whether wrap target application is selected. Whether application of the wrap target is selected may be determined according to the user's selection. Referring to Figure 5, the lap target is applied as the user selects 'Apply Lap target (510)' on the display screen.

In step S180, if application of the wrap target is selected, the calculated average value and (mixed) standard deviation are registered as the wrap target.

In step S180, if application of the lab target is selected, the internal quality control device registers the average value and standard deviation calculated in step S130 as the lab target of the corresponding laboratory, or the average value calculated in step S130 and the mixed standard calculated in step S160. Deviations can be registered as the laboratory's lab target. Referring to Figure 5, the user can select whether to set the average value and calculated (mixed) standard deviation for the quality control material (HLD/LDL QC) as the lab target data of the laboratory.

In step S190, the internal quality control device may receive the application date of the lab target and the selection of whether to apply it. When 'Apply Lab Target (510)' is selected on the display screen in FIG. 5, the display screen as shown in FIG. 6 is displayed. On the display screen of FIG. 6, the user can select the application date and whether to apply the wrap target. Additionally, the application of mixed standard deviation (Pooled SD) may be displayed as 'data source 601' on the display screen. In addition, 'Individual Application' allows you to select multiple target ranges for each test item and reagent concentration, mean value (Mean), standard deviation (SD), coefficient of variation (CV), and minimum and maximum values (Min) of the lab target range ( Max) may be displayed.

Meanwhile, in step S170, only at least one test item for which wrap target application is desired can be selected among a plurality of test items subject to wrap target application, and only the selected test items can be applied as a wrap target. Specifically, it will be described with reference to FIGS. 7 and 8.

Figures 7 and 8 are diagrams for explaining a method in which lap target registration is possible only for at least one specific inspection item in step S170 of Figure 1.

As shown in FIG. 7, on the 'Lab Target Settings' screen on the display screen, the user selects 'Lap Target Application Test Item (701)' and selects the test to which the lap target is applied among a plurality of test items (702). You can select at least one item. Here, when the user selects one test item (HDL-Cholesterol) among the plurality of test items 702, as shown in FIG. 8, the selected test item (HDL-Cholesterol) is displayed on the 'Lab Target Settings' screen of the display screen. Only for Cholesterol), measured values, average values, mixed standard deviation (Pooled SD), and mixed coefficient of variation (CV) can be displayed by date/concentration. If measurement values, etc. are displayed only for the inspection items selected in this way, steps s180 and s190 described above can be performed according to the user's selection.

The method of setting laboratory tolerance ranges using the above-described mixed standard deviation may be configured as a computer-readable recording medium.

Computer-readable recording media includes all types of recording media that store data that can be read by a computer system. Examples of computer-readable recording media include RAM, ROM, CD-ROM, magnetic tape, optical data storage devices, and floppy disks.

Additionally, computer-readable recording media can be distributed across computer systems connected to a network, so that computer-readable code can be stored and executed in a distributed manner. And, functional programs, codes, and code segments for implementing the recording method can be easily deduced by programmers in the technical field to which the present invention pertains.

In addition, the method of setting the laboratory tolerance range using the above-described mixed standard deviation can be implemented as an internal quality control device for medical test data. That is, the quality control method of medical test data or the quality control method of medical test data may be implemented in hardware by consisting of a computer-readable recording medium.

Figure 9 is a diagram for explaining an embodiment of a statistical internal quality control device for medical examination data disclosed in this specification.

Referring to Figure 9, the internal quality control device capable of setting the laboratory tolerance range using the mixed standard deviation includes a control unit 110, an input unit 120, a display unit 130, and a storage unit 140, and a control unit ( 110) may include an interface provider 112. The input unit 120 may be an input device through which a user can input, or may allow input through a network or data transmission. The control unit 110 implements a method of setting a laboratory tolerance range using mixed standard deviation, and is capable of logical and mathematical operations by a central processing unit. The display unit 130 displays data output when applying mixed standard deviation, setting a lab target, or outputting an inquiry, and is a device that displays data analysis results, including quality control data, so that the user can recognize them. The storage unit 140 is a place where quality control data is stored, and can be implemented as a database, and is a device capable of reading and writing data. The interface providing unit 112 outputs data to an output device such as the display unit 130 and provides a means to induce user input. The interface providing unit 112 may be implemented integrally with the control unit 110, or may be implemented as a separate means.

Although the above description focuses on the embodiment, this is only an example and does not limit the invention, and those skilled in the art will understand that there are various options not exemplified above without departing from the essential characteristics of the present embodiment. You will see that variations and applications of branches are possible. For example, each component specifically shown in the embodiments can be modified and implemented. And these variations and differences in application should be interpreted as being included in the scope of the invention defined in the appended patent claims.

110: control unit
112: Interface providing unit
120: input unit
130: Display unit
140: storage unit

Claims (9)

The internal quality control device performs each of the following steps,
An acquisition step of acquiring measurement values measuring test items for at least two or more reagents having different manufacturing numbers;
An average value and standard deviation calculation step of calculating the average value and standard deviation of the measurement values of the target reagent by performing statistical processing on the measurement values of the test items for the target reagent having a manufacturing number different from the reagents;
A mixed standard deviation calculation step of classifying the measured values of the reagents according to the batch numbers of the reagents, calculating a standard deviation for each batch number, and calculating a mixed standard deviation based on the calculated standard deviations for each batch number;
The standard deviation calculated in the average value and standard deviation calculation step is replaced with the mixed standard deviation calculated in the mixed standard deviation calculation step, and the existing target range of the target reagent by the average value and the standard deviation is set to a new A mixed standard deviation application step of changing to a mixed target range; and
A lab target registration step of registering the calculated average value and the calculated mixed standard deviation as a lab target for setting an acceptable range of the laboratory;
Method for setting laboratory tolerance ranges using mixed standard deviation, including.
delete According to claim 1,
A method of setting a laboratory tolerance range using the mixed standard deviation, which calculates the mixed standard deviation based on the standard deviations for each serial number according to the following <mathematical formula>.
<Equation>

In the above <Equation>, SD _Pooled is the mixed standard deviation, n _k is the number of measurements of the reagent with the k (a natural number of 2 or more)th batch number, and SD _k is the standard deviation of the reagent with the kth batch number. .
According to claim 1,
A method of setting a laboratory tolerance range using the mixed standard deviation, where the mixed standard deviation is calculated separately by concentration of quality control substances.
According to claim 1,
Before the average value and standard deviation calculation step, the reagents are categorized by batch number and received and registered, a receipt and registration step. Method for setting a laboratory tolerance range using a mixed standard deviation.
The method of claim 5, wherein the warehousing registration step is,
A method of setting laboratory tolerance ranges using mixed standard deviation in which at least one of the reagent name, application date, manufacturer, expiration date, receipt date, equipment name, and quality control material is received and registered for each batch number. .
The method of claim 1, wherein the lap target registration step includes:
A method of setting a laboratory tolerance range using a mixed standard deviation, in which the application date and application of the lab target are selected, and whether the mixed standard deviation is applied is displayed on a display screen.
The method of claim 1, wherein between the mixed standard deviation application step and the wrap target registration step, at least one test item to be applied as the wrap target is selected from among a plurality of test items to which the wrap target is applied, and the selected test item is selected. A method of setting a laboratory tolerance range using a mixed standard deviation, further comprising applying only test items as the lab target.
A recording medium recording a computer program for executing the method for setting a laboratory tolerance range using the mixed standard deviation according to any one of claims 1, 3 to 8.

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