JP2020128906A - Analysis method, method for creating analytical curve, and automatic analyzer - Google Patents

Abstract

To provide an analysis method, a method for creating an analytical curve, and an automatic analyzer, capable of obtaining measured value variations of a 0 concentration with higher accuracy.SOLUTION: An analysis method includes the steps of: creating an analytical curve on the basis of quantitative analysis of a standard sample in which a content of a substance to be analyzed has a known concentration; acquiring a measured value of an analysis sample by quantitative analysis having a procedure identical to the procedure of the quantitative analysis for the standard sample; when the measured value is within the range of the analytical curve, calculating a concentration of the substance to be analyzed in the analysis sample on the basis of the measured value and the analytical curve; when the measured value is not within the range of the analytical curve, and a concentration corresponding to the measured value is in a negative concentration region, calculating a symmetric measured value symmetric with respect to the measured value using the origin of the analytical curve as a central point, and calculating a concentration of the substance to be analyzed in the analysis sample by subjecting the obtained symmetric measured value to [-1] time processing on the basis of the symmetric measured value and the analytical curve.SELECTED DRAWING: Figure 6

Description

The present invention relates to an analysis method, a calibration curve creation method, and an automatic analyzer.

As an automatic analyzer, a biochemical analyzer that analyzes a biological component contained in a sample such as blood or urine is known. Such an automatic analyzer has a function of measuring the absorbance of a reaction solution obtained by reacting a standard sample whose concentration is known in advance and a reagent, and creating a calibration curve as a concentration-absorbance characteristic. In such an automatic analyzer, in order to know the detection limit of the substance to be analyzed, the absorbance of a plurality of samples not containing the substance to be analyzed is measured, or one sample not containing the substance to be analyzed is measured. It is necessary to obtain the variation in the measured value of 0 concentration by measuring the absorbance of the sample several times.

Therefore, for example, a calibration curve in the negative concentration region near the 0 concentration is created, and the measured value variation of the 0 concentration of the sample containing no substance to be analyzed is obtained using this calibration curve. Regarding the creation of a calibration curve including such a negative concentration region, Japanese Patent Application Laid-Open No. 2004-242242 discloses that "in an analyzer in which a calibration curve in a positive concentration region is represented by a function of a detection signal from a detector, the differential at the origin of the function is obtained. The method is described in which the coefficient is the slope of the calibration curve in the negative concentration region.

Japanese Patent Laid-Open No. 2000-19105

However, the calibration curve in the negative concentration region obtained by such a method is based only on the value at the origin of the calibration curve, and the measurement of 0 concentration obtained from the absorbance of the sample containing no substance to be analyzed. It was difficult to know the value variation accurately.

Therefore, it is an object of the present invention to provide an analysis method, a calibration curve creation method, and an automatic analysis device that can obtain more accurate measurement values of zero concentration.

The present invention to achieve such an object, the step of creating a calibration curve based on the quantitative analysis of a standard sample having a known concentration of the substance to be analyzed, the same as the quantitative analysis of the standard sample A step of obtaining a measurement value of an analysis sample by quantitative analysis of the procedure, and if the measurement value is within the range of the calibration curve, based on the measurement value and the calibration curve, the analysis in the analysis sample In the step of calculating the concentration of the target substance, and when the measured value is not within the range of the calibration curve, a symmetrical measured value in which the measured value is symmetrical with respect to the origin of the calibration curve is calculated, and the symmetrical A method of calculating the concentration of the substance to be analyzed in the analysis sample by subjecting the symmetrical concentration obtained based on the measured value and the calibration curve to [-1] times. The present invention is also an automatic analyzer that carries out this analysis method.

According to the present invention, it is possible to provide an analysis method, a calibration curve preparation method, and an automatic analysis device that can obtain more accurate measurement values of zero concentration variation.

It is a schematic block diagram which shows the automatic analyzer which concerns on embodiment. It is a block diagram of the automatic analysis device concerning an embodiment. It is a follow chart which shows the analysis method of this invention. It is a figure which shows the calibration curve for demonstrating the analysis method of this invention. It is a figure which shows the distribution of the measured value variation of 0 density. It is a figure explaining calculation of the detection limit based on the measured value variation of 0 density.

Hereinafter, embodiments of an analysis method, a calibration curve creation method, and an automatic analysis device of the present invention will be described in detail with reference to the drawings. The analysis method described here is a method for performing a quantitative analysis particularly on a sample in which the concentration of the analysis target substance is near 0 concentration, and for example, in order to know the detection limit of the analysis target substance, the analysis target substance is included. This is a method for obtaining the measured value variation of 0 concentration based on the measured value of the sample not subjected. The automatic analyzer described here is an automatic analyzer for carrying out this analysis method. In addition, here, as an example, a quantitative analysis by an absorptiometric method is illustrated, and the embodiments will be described in order from the configuration of an automatic analyzer that performs this quantitative analysis.

≪Automatic analyzer≫
FIG. 1 is a schematic configuration diagram showing an automatic analyzer 1 according to an embodiment. As an example, the automatic analyzer 1 according to the present invention is applied to a biochemical analyzer for analyzing biological components contained in a sample such as blood or urine. It is a schematic block diagram of. In particular, this automatic analyzer 1 is equipped with a mechanism for diluting a sample with a diluent. Such an automatic analyzer 1 includes a measuring unit 1a and a control unit 1b.

Of these, the measurement unit 1a includes, for example, a sample holding unit 2, a dilution container holding unit 3, a first reagent holding unit 4, a second reagent holding unit 5, and a reaction container holding unit 6. Further, the measuring unit 1 a includes a dilution stirring device 11, a dilution cleaning device 12, a first reaction stirring device 13, a second reaction stirring device 14, a measuring unit 15, and a reaction container cleaning device 16.

The measuring unit 1a also includes a plurality of dispensing devices 20. Here, each of the dispensing devices 20 is, for example, four of a sample dispensing device 20a, a diluted sample dispensing device 20b, a first reagent dispensing device 20c, and a second reagent dispensing device 20d.

FIG. 2 is a block diagram of the automatic analyzer according to the embodiment. As shown in this figure, the control unit 1b includes a display unit 51, an input unit 52, a storage unit 53, an arithmetic processing unit 54, and a drive control unit 55.

Hereinafter, based on FIGS. 1 and 2, the details of these constituent elements will be described in the order of the measurement unit 1a and the control unit 1b.

<Measuring section 1a>
[Sample holder 2]
The sample holder 2 is, for example, of a turntable type, and is configured to hold a plurality of sample containers T2 in a plurality of rows along the peripheral edge thereof and convey the held sample containers T2 in both directions in the circumference. .. The sample holding unit 2 is rotatably supported along the circumferential direction by a drive mechanism (not shown). Each sample container T2 held in the sample holding unit 2 stores a sample to be tested and other solutions. The sample holding unit 2 is configured to hold various samples at predetermined positions. Such a sample holding unit 2 may have a function of cooling the held sample container T2 and other containers.

[Dilution container holder 3]
The dilution container holding unit is, for example, of a turntable type, configured to hold a plurality of dilution containers T3 along the periphery thereof and convey the held dilution containers T3 bidirectionally around the circumference. The dilution container holder 3 is rotatably supported along the circumferential direction by a drive mechanism (not shown). The sample aspirated from the sample container T2 arranged in the sample holder 2 and the diluent are dispensed into the dilution container T3 held in the dilution container holder 3.

[First Reagent Holding Section 4 and Second Reagent Holding Section 5]
The first reagent holding unit 4 is, for example, of a turntable shape, and holds a plurality of first reagent containers T4 along the periphery thereof. The second reagent holder 5 is, for example, of a turntable shape and holds a plurality of second reagent containers T5 along the periphery thereof. Then, the first reagent container T4 and the second reagent container T5, which are respectively held, are conveyed in both directions of the circumference. The first reagent holding part 4 and the second reagent holding part 5 are rotatably supported in the circumferential direction by a driving mechanism (not shown). The reagent holding section provided in the automatic analyzer 1 is not limited to two, the first reagent holding section 4 and the second reagent holding section 5, and may be one or three or more. May be plural. In the case where the automatic analyzer 1 has only one reagent holding section, a first reagent dispensing apparatus 20c and a second reagent dispensing apparatus 20d described below are provided corresponding to one reagent holding section. May have different configurations.

[Reaction container holding part 6]
The reaction container holding unit 6 is arranged between the dilution container holding unit 3, the first reagent holding unit 4, and the second reagent holding unit 5. The reaction container holding unit 6 is, for example, in the form of a turntable, and is configured to hold a plurality of reaction containers T6 along its periphery and convey the held reaction containers T6 bidirectionally in the circumference. The reaction container holding unit 6 is rotatably supported along the circumferential direction by a drive mechanism (not shown). The reaction container T6 held in the reaction container holding unit 6 includes the diluted sample collected from the dilution container T3 of the dilution container holding unit 3, the first reagent collected from the first reagent container T4 of the first reagent holding unit 4, and the The second reagent collected from the second reagent container T5 of the two-reagent holding unit 5 is dispensed in a predetermined amount. Then, in the reaction container T6, the diluted sample and the first reagent and the second reagent are stirred to perform these reactions, or the diluted sample and the first reagent are stirred to perform these reactions. .. In addition, in the reaction container T6, the first reagent and the second reagent that are stirred together with the diluted sample are selected according to the inspection item to be performed on each sample.

The reaction container holding unit 6 as described above is configured so as to always keep the temperature of the reaction container T6 constant by a constant temperature tank (not shown).

[Dilution stirrer 11]
The dilution stirring device 11 is arranged around the dilution container holding unit 3. The dilution stirring device 11 has a stirring mechanism and a driving mechanism for driving the stirring mechanism. The diluting stirring device 11 stirs the sample and the diluting liquid in the diluting container T3 held by the diluting container holding section 3 to obtain a diluted sample in which the sample and the diluting liquid are mixed.

[Dilution washing device 12]
The dilution cleaning device 12 is arranged around the dilution container holding unit 3. The dilution cleaning device 12 is a device that cleans the dilution container T3 after the diluted sample is sucked by the diluted sample dispensing device 20b described below.

[First Reaction Stirrer 13 and Second Reaction Stirrer 14]
The first reaction stirrer 13 and the second reaction stirrer 14 are arranged around the reaction container holder 6. The first reaction stirrer 13 and the second reaction stirrer 14 stir the diluted sample and the first reagent or the second reagent in the reaction container T6 held by the reaction container holder 6 to obtain the diluted sample, The reaction between the first reagent and the second reagent proceeds. The first reaction stirrer 13 and the second reaction stirrer 14 may be of the same configuration as the dilution stirrer 11.

[Measurement unit 15]
The measuring unit 15 is arranged so as to face the outer wall of the reaction container holding unit 6 around the reaction container holding unit 6. The measuring unit 15 is a multi-wavelength photometer that performs optical measurement on the diluted sample that has reacted with the first reagent and the second reagent corresponding to the test item in the reaction container T6, and measures the various components in the sample. The amount is output as the absorbance and the reaction state of the diluted sample is detected.

[Reaction container cleaning device 16]
The reaction container cleaning device 16 is arranged around the reaction container holding unit 6. The reaction container cleaning device 16 is a device for cleaning the inside of the reaction container T6 whose inspection has been completed.

[Sample Dispensing Device 20a]
The sample dispensing device 20 a includes a sample probe 21 a as a thin tubular dispensing probe 21, and is arranged around the sample holding unit 2 and the dilution container holding unit 3. The sample dispensing device 20a is configured such that the tip of the sample probe 21a is inserted into the dilution container T3 of the dilution container holding unit 3 and the sample aspirated into the sample probe 21a and a predetermined amount of the sample supplied from the sample dispensing device 20a itself. A diluting liquid (for example, physiological saline or pure water) is discharged into the diluting container T3. As a result, the sample is diluted to a predetermined dilution ratio in the dilution container T3. Further, the sample dispensing apparatus 20a as described above includes a cleaning mechanism not shown here, and is configured to clean the sample probe 21a for each dispensing operation.

[Diluted sample dispensing device 20b]
The diluted sample dispensing device 20b is one of the dispensing devices 20, and includes a diluted sample probe 21b as a thin tube-shaped dispensing probe 21, and is provided between the dilution container holding unit 3 and the reaction container holding unit 6. It is arranged. The diluting sample dispensing device 20b inserts the tip of the diluting sample probe 21b into the diluting container T3 of the diluting container holding unit 3 by a drive mechanism (not shown) according to a preset measurement program, and fills it with system water. A predetermined amount of diluted sample is sucked from the tip of the diluted sample probe 21b. At this time, the diluted sample probe 21b sucks the diluted sample in an amount corresponding to the measurement item set for each sample from the dilution container T3, and discharges the sucked diluted sample into the reaction container T6. As a result, the diluted sample dispensing device 20b dispenses the diluted sample in an amount corresponding to the measurement item from the dilution container T3 into the reaction container T6. The diluted sample dispensing device 20b as described above includes a cleaning mechanism (not shown), and is configured to clean the diluted sample probe 21b for each dispensing operation.

[First Reagent Dispensing Device 20c, Second Reagent Dispensing Device 20d]
The first reagent dispensing device 20c and the second reagent dispensing device 20d are one of the dispensing devices 20 and have the same configuration as the other dispensing devices, and include the reaction container holding unit 6 and the first dispensing device 20. It is arranged between the reagent holding unit 4 and the second reagent holding unit 5. The first reagent dispensing device 20c dispenses the first reagent from the first reagent container T4 of the first reagent holding unit 4 to the reaction container T6 according to a preset measurement program. The second reagent dispensing device 20d dispenses the second reagent from the second reagent container T5 of the second reagent holding unit 5 into the reaction container T6 according to a preset measurement program.

Further, the first reagent dispensing apparatus 20c and the second reagent dispensing apparatus 20d as described above include a cleaning mechanism (not shown), and a reagent probe provided for each dispensing operation. 21c and 21db are cleaned.

<Control unit 1b>
The control unit 1b is connected to the drive mechanism of each of the constituent elements of the measuring unit 1a described above and the measuring unit 15. Such a control unit 1b includes a display unit 51, an input unit 52, a storage unit 53, an arithmetic processing unit 54, and a drive control unit 55 which are connected to each other. Of these, the storage unit 53, the arithmetic processing unit 54, and the drive control unit 55 are configured by a computer such as a microcomputer. The computer includes a storage unit such as a CPU (Central Processing Unit), a ROM (Read Only Memory) and a RAM (Random Access Memory), and controls the operation of each unit in the automatic analyzer 1. The storage unit such as the ROM and the RAM may be the storage unit 53. Hereinafter, details of each component of the control unit 1b will be described.

[Display 51]
The display unit 51 displays the measurement result of the measuring unit 15 and also displays various setting information and various history information in the automatic analyzer 1. For the display unit 51, for example, a liquid crystal display device or the like is used.

[Input unit 52]
The input unit 52 receives inputs relating to various settings made by the operator of the automatic analyzer 1 and other inputs, and outputs an input signal to the drive control unit 55. For the input unit 52, for example, a mouse, a keyboard, a touch panel provided on the display surface of the display unit 51, or the like is used. The input unit 52 also includes, for example, a bar code reader that reads the bar code of the sample container T2 held by the sample holding unit 2.

[Storage unit 53]
The storage unit 53 is configured by a large-capacity recording device such as an HDD (Hard disk drive) or a semiconductor memory, for example. The storage unit 53 stores various programs executed by the arithmetic processing unit 54 and the drive control unit 55, which will be described below, and various setting information for executing the programs. These pieces of information are information stored in the storage unit 53 in advance or stored in the storage unit 53 based on the input from the input unit 52.

[Arithmetic processing unit 54]
The arithmetic processing unit 54 determines the control for analysis by the drive control unit 55 based on the input from the input unit 52 and the information stored in the storage unit 53. The arithmetic processing unit 54 also creates a calibration curve based on the result measured by the measuring unit 15. The procedure of the determination of the control and the preparation of the calibration curve for the analysis performed by the arithmetic processing unit 54 will be described in detail in the next automatic analysis method.

[Drive control unit 55]
The drive control unit 55 controls the operation of the drive mechanism of each unit constituting the measurement unit 1a based on the signals from the input unit 52, the storage unit 53, and the arithmetic processing unit 54, and the sample container T2 of the sample holding unit 2 is controlled. The sample contained in the sample is analyzed.

≪Analysis method≫
FIG. 3 is a follow chart showing the analysis method of the present invention. Part of the procedure of the analysis method shown in this flowchart is performed by the CPU configuring the arithmetic processing unit 54 and the drive control unit 55 described with reference to FIG. 2 executing the program stored in the storage unit 53. To be done. Hereinafter, an embodiment of the analysis method of the present invention will be described in the order of steps of the flowchart of FIG. 3 with reference to other drawings as necessary.

<Acquisition method of concentration based on calibration curve>
[Step S101]
First, in step S101, a calibration curve [L] is created according to a normal procedure. In this case, the drive control unit 55 controls the drive mechanism of each unit in the measurement unit 1a according to the input from the input unit 52, and performs the analysis for creating the calibration curve [L]. That is, the absorbance of a reaction solution obtained by reacting a standard sample whose concentration of the substance to be analyzed is known with a reagent is measured to obtain a calibration curve [L] as a concentration-absorbance characteristic. Usually, the absorbance is measured using two types of standard samples having different concentrations of the substance to be analyzed, but the absorbance is measured for three or more types of standard samples having different concentrations depending on the inspection item. After the measurement of the absorbance is completed, the arithmetic processing unit 54 creates a calibration curve [L] based on the absorbance obtained by the measurement.

FIG. 4 is a diagram showing a calibration curve [L] for explaining the analysis method of the present invention. This calibration curve [L] is, for example, when the absorbance is measured using five kinds of standard samples having different concentrations. As shown in this figure, in preparing the calibration curve [L], the concentration [C] is plotted on the X-axis, and the measured absorbance value [r] (signal intensity) is plotted on the Y-axis. Then, based on the points P1 to P5 in which the measured values of the absorbance of the five types of standard samples are plotted and the functions shown in the following 1) to 5) for creating the approximate curve, the calibration curve [L ] Is created.

1) polygonal line: between points P1~P5 Y = ax + 2 ones were connected in b) Spline: 3 between points P1 to P5 those tethered by ^{Y = aX 3 + bX 2 +} cX + d) LOGIT-LOG1: Y = ( a-d)/(1+X/b)+d
4) LOGIT-LOG2: Y=(ad)/{1+(X/b) ^C }+d
5) LOGIT-LOG3: Y=(ad)/{1+(X/b) ^C *exp(eX)}+d

Note that, in FIG. 4, the calibration curve [L] shows the case where the absorbance at the concentration [C]=0 is not zero [0], but the calibration curve [L] created here is the concentration [C]. The absorbance at =0 may be zero [0].

[Step S102]
Next, in step S102, the measurement value [r] of the analysis sample to be analyzed is acquired. In this case, according to the input from the input unit 52, the drive control unit 55 controls the drive mechanism of each unit in the measurement unit 1a and performs the analysis for acquiring the measurement value [r] of the analysis sample to be analyzed. carry out. For example, for the purpose of obtaining the measured value variation of 0 concentration, the absorbance of a sample (blank sample) containing no substance to be analyzed is measured, and the signal intensity thereof is obtained as the measured value [r]. At this time, the measurement of the absorbance is performed in the same procedure as the measurement of the absorbance of the standard sample performed in the preparation of the calibration curve [L].

[Step S103]
Next, in step S103, the arithmetic processing unit 54 determines whether or not the measurement value [r] obtained in step S102 is within the range of the calibration curve [L] created in step S101. Here, “within the range of the calibration curve [L]” means that the measured value [r] corresponds to each concentration of each standard sample used to create the calibration curve [L] Within the range, it means that the concentration [C] can be read by fitting the measured value [r] to the calibration curve [L].

For example, the measured value [r]=[r1] shown in FIG. 4 is within the range of each absorbance corresponding to each concentration of the points P1 to P5 in the calibration curve [L], and by applying it to the calibration curve [L]. , The corresponding density [C]=[C1] can be read. Therefore, the measured value [r1] is determined to be within the range of the calibration curve [L] (YES). In this case, the process proceeds to the next step S104.

On the other hand, the measured value [r]=[r2] and the measured value [r]=[r3] shown in FIG. 4 are outside the range of each absorbance corresponding to each concentration of P1 to P5 in the calibration curve [L], The corresponding concentration [C] cannot be read from the calibration curve [L]. Therefore, it is determined that the measured values [r2] and [r3] are not within the range of the calibration curve [L] (NO). In this case, the process proceeds to step S105.

[Step S104]
When the process proceeds to step S104, the arithmetic processing unit 54 applies the measurement value [r]=[r1] obtained in step S102 to the calibration curve [L] created in step S101 to obtain the measurement value [r1]. The corresponding concentration [C]=[C1] is obtained from the calibration curve [L]. Then, a series of analysis processing is ended.

[Step S105]
On the other hand, if the process proceeds to step S105, the arithmetic processing unit 54 determines whether the concentration corresponding to the measurement value [r] obtained in step S102 is in the negative concentration region. At this time, the arithmetic processing unit 54 makes the following determination depending on whether the calibration curve [L] is monotonically increasing or monotonically decreasing.

That is, when the calibration curve [L] has a monotonically increasing value as illustrated, the arithmetic processing unit 54 causes the measurement value [r] to be a value lower than the absorbance [r0] at the origin O of the calibration curve [L]. If so, it is determined that the concentration corresponding to the measured value [r] is in the negative concentration region (YES). Therefore, when the measured value [r] obtained in step S102 is the measured value [r]=[r2], the arithmetic processing unit 54 determines that the concentration corresponding to the measured value [r2] is in the negative concentration region (YES). Then, the process proceeds to step S106. On the other hand, when the measured value [r] obtained in step S102 is the measured value [r]=[r3], the arithmetic processing unit 54 determines that the density corresponding to the measured value [r3] is not in the negative density region ( It is determined to be NO), and the process ends.

When the calibration curve [L] is a monotonous decrease in which the concentration [C] decreases with an increase in the measurement value [r], the arithmetic processing unit 54 causes the measurement value [r] to decrease. Is larger than the absorbance [r0] at the origin O of the calibration curve [L], it is determined that the concentration corresponding to the measured value [r] is in the negative concentration region (YES), and the process proceeds to step S106. In other cases, the arithmetic processing unit 54 determines that the concentration corresponding to the measured value [r] is not in the negative concentration region (NO), and ends the process.

[Step S106]
In step S106, the arithmetic processing unit 54 calculates the symmetrical measurement value [rs] of the measurement value [r]=[r2] obtained in step S102. Here, the symmetrical measurement value [rs] is a symmetrical value of the measurement value [r2] with respect to the origin O of the calibration curve [L]. Here, the origin O is the intersection of the concentration [C]=0 and the absorbance corresponding to the concentration [C]=0 in the calibration curve [L].

[Step S107]
Next, in step S107, the arithmetic processing unit 54 calculates the concentration of the symmetrical measurement value [rs] obtained in step S106 as the symmetrical concentration [Cs] based on the calibration curve [L] created in step S101. Here, by applying the symmetrical measurement value [rs] to the calibration curve [L], the symmetrical concentration [Cs] corresponding to the symmetrical measurement value [rs] is acquired from the calibration curve [L].

[Step S108]
Next, in step S108, the arithmetic processing unit 54 performs a process of multiplying the symmetrical concentration [Cs] calculated in step S107 by [-1], and the concentration [C2] calculated by this process is measured value [r2]. Is acquired as the concentration corresponding to. The density [C]=[C2] thus obtained has a negative value. After the negative concentration [C]=[C2] corresponding to the measured value [r2] is obtained as described above, the series of analysis processes is terminated.

The negative concentration [C]=[C2] thus obtained is a value obtained based on the calibration curve [L] created from the measured values of the standard sample whose concentration is known. That is, the point P6 where the negative concentration [C2] obtained here and the measured value [r2] intersect is a virtual calibration curve in which the calibration curve [L] created in step S101 is point-symmetric with respect to the origin O. It is located above [Ls]. The hypothetical calibration curve [Ls] is obtained by making the calibration curve [L] point-symmetric with respect to the origin O, so that the shape of the calibration curve [L] is maintained in the negative concentration region, and the negative concentration is also negative. It has good continuity with the calibration curve [L] in the region.

The above steps S106 to S108 are similarly performed even if the calibration curve [L] is monotonically decreasing.

<Modification of concentration acquisition method based on calibration curve>
As described above, the point P6 where the negative concentration [C2] obtained in step S108 and the measured value [r2] intersect is point-symmetric with respect to the origin O of the calibration curve [L] created in step S101. Since it is located on the virtual calibration curve [Ls], the following modified example can be presented as a method of acquiring the concentration [C] based on the calibration curve [L].

That is, first, the arithmetic processing unit 54 creates a calibration curve [L] in step S101, then creates a virtual calibration curve [Ls] with this calibration curve [L] point-symmetric with respect to the origin O, and then the calibration curve. [L] and the virtual calibration curve [Ls] may be continuous to form a calibration curve ([L]+[Ls]) including a negative concentration region.

In this case, after creating the calibration curve ([L]+[Ls]) including the negative concentration region, the measurement value [r] for the analysis sample is acquired as described in step S102. Next, the arithmetic processing unit 54, based on the obtained measured value [r] and the calibration curve ([L]+[Ls]) including the negative concentration region, the concentration [C] corresponding to the measured value [r]. Should be calculated.

Further, the above-described modified example is similarly executed even if the calibration curve [L] is monotonically decreasing.

<Calculation of variations in measured values>
In order to obtain a measurement value variation of 0 concentration by applying any of the concentration acquisition methods described above, a plurality of samples (blank samples) that do not contain the substance to be analyzed are used as analysis samples, and the concentration of these analysis samples is To get. In this case, the concentration [C] of each analytical sample is typically calculated by applying any of the above-described concentration acquisition methods to 10 analytical samples. Then, using the concentration [C] calculated for the obtained 10 analysis samples (blank samples), the variation in the measured value of 0 concentration is obtained. In order to obtain such a variation in the measured value of 0 concentration, the drive control unit 55 controls the drive mechanism of each unit of the measurement unit 1a in accordance with the input from the input unit 52, so that 10 samples (blank samples) can be obtained. The analysis is performed, and the calculation processing unit 54 calculates the concentration [C] of each analysis sample based on the measurement value obtained by this analysis.

FIG. 5 is a diagram showing a distribution of measured value variations of 0 density. As shown in this figure, a distribution of 0 concentration can be obtained from the concentrations calculated for 10 analysis samples (blank samples) that do not contain the substance to be analyzed. In addition, in the calculation of the above-mentioned variation of the measured values, the case where the absorbance measurement is carried out for each of a plurality of samples (for example, 10 samples) not containing the substance to be analyzed has been described. However, the measurement value variation may be calculated by using the measurement value [r] obtained by performing the absorbance measurement a plurality of times (for example, 10 times) for one sample that does not contain the substance to be analyzed.

In addition, in order to obtain the detection limit of the substance to be analyzed in the analysis method or the analyzer that has carried out the analysis method from the above-mentioned variation in the measured values, the standard sample of known plural concentrations in which the concentration of the substance to be analyzed is near 0 For, the measured value variation is obtained as described above.

FIG. 6 is a diagram for explaining the calculation of the detection limit based on the variation in the measured value of 0 concentration, and for the standard sample in which the concentration of the analysis target substance is the known sample concentration [Cst0], [Cst1], [Cst2] The density [C] calculated by the acquisition method described above is shown. As shown in the figure, the concentration [C] calculated for each of the 10 standard samples of each sample concentration [Cst0], [Cst1], and [Cst2] is a value having variations.

In the above-described analysis method or the analysis apparatus that has performed the analysis method, from FIG. 6, the range of variation between the sample concentration [Cst0] of the sample not containing the substance to be analyzed and the calculated concentration [C] does not overlap. The sample concentration [Cst2] of the sample can be obtained as the detection limit of the substance to be analyzed.

<<Effect of Embodiment>>
As described above, according to the analysis method and the automatic analysis device of the embodiment, even if a measurement value indicating a negative concentration is obtained for an analysis sample in which the content of the substance to be analyzed is near 0 concentration, a negative value is obtained. The shape of the calibration curve [L] is maintained in the concentration region, and the concentration can be calculated based on the virtual calibration curve [Ls] having good continuity with the calibration curve [L]. As a result, for example, in the quantitative analysis of a plurality of samples that do not contain the substance to be analyzed, the 0 concentration variation of the calculated concentration can be approximated to the normal distribution including the negative concentration region as shown in FIG. It is possible to obtain a variation in the measured value of zero density. As a result, it becomes possible to more accurately obtain the detection limit for the analysis target substance of the analysis method and the analysis apparatus that implements the analysis method, and improve the reliability of the performance evaluation of the analysis method and the analysis apparatus. Will be possible.

[C], [C1], [C2]... Concentration O... Origin of calibration curve [Cr]... Symmetrical concentration [Cst]... Known sample concentration [L]... Calibration curve [Ls]... Virtual calibration curve [r], [R1], [r2], [r3]...measured value [rs]...symmetric measured value

Claims (9)

A step of creating a calibration curve based on a quantitative analysis of a standard sample having a known concentration of the substance to be analyzed,
Acquiring a measurement value of an analytical sample by a quantitative analysis in the same procedure as the quantitative analysis of the standard sample,
If the measured value is within the range of the calibration curve, based on the measured value and the calibration curve, a step of calculating the concentration of the substance to be analyzed in the analysis sample,
When the measured value is not within the range of the calibration curve, and the concentration corresponding to the measured value is in the negative concentration region, a symmetric measured value in which the measured value is symmetrical with respect to the origin of the calibration curve is used. A step of calculating the concentration of the substance to be analyzed in the analytical sample by subjecting the symmetrical concentration obtained based on the symmetrical measured value and the calibration curve to [-1] times. .. A step of creating a calibration curve based on a quantitative analysis of a standard sample having a known concentration of the substance to be analyzed,
A step of creating a calibration curve including a negative concentration region by continuing a virtual calibration curve in which the calibration curve is point-symmetric with respect to the origin of the calibration curve, and the calibration curve;
Acquiring a measurement value of an analytical sample by a quantitative analysis in the same procedure as the quantitative analysis of the standard sample,
Calculating the concentration of the substance to be analyzed in the analysis sample based on the measured value and a calibration curve including the negative concentration region. A sample that does not contain the substance to be analyzed is used as the analysis sample, the step of obtaining the measured value for the analysis sample and the steps of calculating the concentration of the substance to be analyzed are carried out a plurality of times, and the concentration is calculated from the calculated concentration. The analysis method according to claim 1, wherein a measurement value variation of zero concentration in the quantitative analysis is obtained. When obtaining the measured value variation of zero concentration, a plurality of samples that do not contain the substance to be analyzed are the analysis samples, and the step of obtaining the measured value for each of the analysis samples and the concentration of the substance to be analyzed are calculated. The analysis method according to claim 3, wherein each of the steps is performed. When obtaining a measurement value variation of zero concentration, one sample not containing the analysis target substance is used as the analysis sample, the step of obtaining the measurement value for the analysis sample, and the concentration of the analysis target substance are calculated. The analysis method according to claim 3, wherein each step is performed a plurality of times. A plurality of samples in which the content of the substance to be analyzed has a known concentration is used as the analysis sample, and the step of obtaining the measured value for each of the analysis samples and the steps of calculating the concentration of the substance to be analyzed are performed. A step of obtaining a measured value variation of a known concentration in the quantitative analysis from the calculated concentration,
The analysis method according to claim 3, further comprising a step of obtaining a detection limit in the quantitative analysis from the measured value variation of the zero concentration and the measured value variation of the known concentration. A step of creating a calibration curve based on a quantitative analysis of a standard sample having a known concentration of the substance to be analyzed,
And a virtual calibration curve in which the calibration curve is point-symmetric with respect to the origin of the calibration curve is connected to the calibration curve to create a calibration curve including a negative concentration region. An analysis unit having a measurement unit for performing optical measurement of the sample reacted with the reagent, and an arithmetic processing unit for calculating the concentration of the substance to be analyzed in the sample based on the measurement value measured by the measurement unit. An automatic analyzer for performing quantitative analysis of a substance to be analyzed contained in the sample,
The arithmetic processing unit,
Create a calibration curve based on the quantitative analysis of a standard sample with a known concentration of the substance to be analyzed,
When the measured value of the analytical sample obtained by the quantitative analysis of the same procedure as the quantitative analysis of the standard sample is within the range of the calibration curve, based on the measured value and the calibration curve, the analytical sample The concentration of the substance to be analyzed in, the measured value is not within the range of the calibration curve, and when the concentration corresponding to the measured value is in the negative concentration region, the measured value of the calibration curve The substance to be analyzed in the analysis sample is calculated by calculating a symmetrical measurement value that is symmetrical with respect to the origin, and subjecting the symmetrical concentration obtained based on the symmetrical measurement value and the calibration curve to [-1] times. Automatic analyzer that calculates the concentration of. An analysis unit having a measurement unit for performing optical measurement of the sample reacted with the reagent, and an arithmetic processing unit for calculating the concentration of the substance to be analyzed in the sample based on the measurement value measured by the measurement unit. An automatic analyzer for performing quantitative analysis of a substance to be analyzed contained in the sample,
The arithmetic processing unit,
Create a calibration curve based on the quantitative analysis of a standard sample with a known concentration of the substance to be analyzed,
A calibration curve including a negative concentration region is created by continuing a virtual calibration curve with the calibration curve being point-symmetric with respect to the origin of the calibration curve,
An automatic calculation of the concentration of the substance to be analyzed in the analytical sample based on the measurement value of the analytical sample obtained by the quantitative analysis in the same procedure as the quantitative analysis of the standard sample and the calibration curve including the negative concentration region. Analysis equipment.

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