JP2000131323A - Adjusted and controlled serum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the matrix effect of a controlled serumd and to ensure the same reactivity as that of human fresh serum by a method, wherein the controlled serum which contains a buffer is changed into a human serum albumin aqueous solution or an animal serum albumin aqueous solution. SOLUTION: This adjusted and controlled serum is a controlled serum, in which human fresh blood is used as a raw material, so as to perform a fibrin removal treatment or a fibrin and lipid removal treatment, or the buffer capacity of a serum albumin is adjusted. It is preferable that the buffer capacity be adjusted by adding a buffer. As the buffer, a bicarbonate, an ammonium salt, an acetate, a phosphate or the like is used. An adjusting method for the adjusted and controlled serum is applied to an albumin which is put on the market, such as a human serumd albumin, a bovine serum albumin or the like, and the adjusted and controlled serum can be obtained. As the buffer which is added to the serum albumine, it is preferable to use a bicarbonate or 6- aminocaproic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a control serum used for measuring various components in serum or a control serum used as a calibration substance (calibrator) in clinical tests.

[0002]

2. Description of the Related Art A control serum used for a clinical test is used for preparing a calibration curve or for diluting a specimen.

[0003] Generally, the control serum is composed of human serum, human plasma, and human serum albumin (HS) as matrix components.
A), a biological protein such as bovine serum albumin (BSA) is used as a raw material. Actually, after removing blood cells from blood, fibrin, which is a fibrin removed, fibrin and lipids removed, and fibrin etc. removed and added with specific additives are commercially available as control serum. Have been. As those using HSA, defibrinated plasma, off-cloth serum, and the like are commercially available.

[0004] In the control serum, the matrix effect is different from that of fresh serum obtained from humans (hereinafter referred to as human fresh serum). Therefore, there is a difference between the measured values when the control serum is used and when the human fresh serum is used. The matrix effect is an effect of an unknown component included in a matrix around a measurement target component (analyte). It is believed that this unknown component has some effect on the measurement. The chemical element of the matrix is p
H, carbon dioxide, total protein, buffer capacity, ionic strength, stabilizers, preservatives, chemical components and the like. The physical elements are
Viscosity, surface tension, etc.

[0005] As an example of the matrix effect, the influence of the matrix effect of a calibration standard solution on phenytoin measurement has been reported (Clinical Chemis).
try 42:10, 1645-1653, 199
6).

In order to solve the above problems, it is necessary to adjust the control serum to have physicochemical properties close to fresh human serum. Several methods have been developed to solve this problem in clinical laboratory standards that are used for the same applications as control sera. For example, a standard solution in which the ion activity coefficient is adjusted for ion measurement by an ion electrode method (Japanese Patent Application Laid-Open No. 61-34455), and a standard solution in which the viscosity and specific gravity are approximated to human serum by adding polyethylene glycol or the like. (JP-B-7-104344 and JP-A-9-89899).

[0007] By adding commercially available albumin such as human serum albumin and bovine serum albumin, it is possible to prepare a standard solution for clinical tests having the same specific gravity and viscosity as fresh human serum. Since albumin often contains enzymes to be measured and nitrogen-containing components (creatine, uric acid, etc.), there is a problem in adjusting the matrix effect by using these serum albumins.

It is also known that a difference occurs in measured values between dry chemistry (dry method) and wet chemistry (liquid method) due to the matrix effect of control serum (Clinica Chimica Act).
a, 113, 293-303, 1981, Medica
l Technology 21 (3), 257, 19
93 and Clinical Chemistry, Vol. 25, Supplement, 18a, 196
6).

[0009] Therefore, there is a demand for the development of a control serum that adjusts the matrix effect of the conventional control serum to ensure the same reactivity as fresh human serum.

[0010]

SUMMARY OF THE INVENTION The present invention provides a buffer chemistry similar to that of human fresh serum in dry chemistry in order to reduce the discrepancy between measured values of human fresh serum and control serum due to a difference in matrix effect in dry chemistry. It is to provide a preparation control serum having the following. Another object of the present invention is to provide a control serum prepared by adjusting the buffering capacity of the control serum so as to reduce the difference between the measured values in the dry chemistry and the wet chemistry.

[0011]

Means for Solving the Problems According to the present inventors, a control serum containing a buffer, wherein 1 mL per 1 mL of the control serum is used.
Normal hydrochloric acid aqueous solution 10μL, 20μL, 30μL, 40μ
L, and respective pH values when titrated with 50 [mu] L Y _A is, in each titration conditions, pH 4 to 7.
7, the following formula: 0.0002 × (X _A ) ² −0.0628 × (X _A ) +
7.0521 ≦ Y _A ≦ 0.0002 × (X _A ) ² -0.
Wherein, X _A represents a drip quantitative] 0628 × (X _A) +8.2521 satisfied, and the management serum 1 N sodium hydroxide solution for 1 mL 1
When Y _B , which is the pH value when titrated with 0 μL, 20 μL, 30 μL, 40 μL, and 50 μL, is in the range of pH 7.7 to 11 under each titration condition, the following formula: −0.0009 × (X _B ) ² + 0.0971 × (X _B )
+ 7.1521 ≦ Y _B ≦ −0.0009 × (X _B ) ² +
0.0971 × (X _B ) +8.3521 [wherein X _B represents the titer] It has been found that a regulated serum capable of solving the above-mentioned problem is characterized by satisfying the formula:

A preferred embodiment of the serum for controlling and controlling is as follows. (1) An adjusted control serum, wherein the control serum containing a buffer is a human serum albumin aqueous solution or an animal serum albumin aqueous solution containing a buffer. (2) A controlled serum, wherein the buffer is a bicarbonate or an ammonium salt. (3) A controlled serum, wherein the buffer is an organic compound having a pKa in the range of 2.76 to 4.76 and in the range of 9.33 to 11.33. Organic compounds
Preferably, it is 6-aminocaproic acid.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The regulated control serum of the present invention is a commercially available control serum such as one subjected to defibrin treatment using fresh human blood as a raw material, one subjected to defibrin and delipidation treatment, or a commercially available serum. This is a result of adjusting the buffering capacity of albumin.

It is preferable that the buffering capacity of the adjusted control serum is similar to that of fresh human serum. Since the buffering capacity is an amount indicated by the ratio of the amount of base or acid added to the buffer to the change in the pH of the solution, the approximation of the buffering capacity means that the pH titration curve of the adjusted control serum is a human fresh serum. Corresponds to the pH titration curve of That is, the former is preferably in the range of pH 0.6 with respect to the latter. pH
In the range of 4 to 11, the former has a pH of 0.
More preferably, it is within the range of 6.

Here, the pH titration curve of a typical representative human fresh serum can be expressed as a theoretical quadratic curve by calculation (FIG. 1). Acid side (pH 4 ~
7.7) and the alkaline side (pH 7.7 to 11) are represented by the following formulas (1) and (2), respectively. (1) Y = 0.002 × (X) ² −0.0628 × (X) +
7.6521 (2) T = −0.0009 × (S) ² + 0.0971 × (S)
+7.7521, where Y is 10 μL, 20 μL, 30 μL, 40 μL, 50 μL of 1 N aqueous hydrochloric acid solution per 1 mL of human fresh serum.
The pH when titrated with L, X indicates the titer, and T
Are 10 μL, 20 μL, 30 μL, 40 μL, 5 μL of 1 N aqueous sodium hydroxide solution per 1 mL of human fresh serum.
The pH when titrated with 0 μL, and S indicates the titer.

The fact that the pH titration curve of the adjusted control serum is within the range of pH 0.6 with respect to the pH titration curve of the fresh human serum can be explained as follows. 1 mL of 1N hydrochloric acid aqueous solution, 10 μL, 20 μL, 30 μ
L, 40 μL, and 50 μL, respectively.
Is H Y _A is, in each titration conditions, pH 4
In the range of ７7.7, the following formula (3): (3) 0.0002 × (X _A ) ² −0.0628 × (X _A ) +
7.0521 ≦ Y _A ≦ 0.0002 × (X _A ) ² -0.
0628 × (X _A ) +8.2521 (X _A represents the titer), and 10 μL of a 1 N aqueous sodium hydroxide solution per 1 mL of the control serum.
L, 20 μL, 30 μL, 40 μL, and 50 μL when titrated with 50 μL, Y _B , which is the respective pH, is in the range of pH 7.7 to 11 under the respective titration conditions, and the following formula (4): (4) -0. 0009 × (X _B ) ² + 0.0971 × (X _B )
+ 7.1521 ≦ Y _B ≦ −0.0009 × (X _B ) ² +
0.0971 × (X _B ) +8.3521 (X _B represents the titer).

Therefore, as shown in FIG. 1, the pH-regulated region of the serum for preparation and control of the present invention is, as shown in FIG. 1, a curve obtained by translating the pH titration curve of human fresh serum by 0.6 in the positive direction and a curve in the negative direction. This is a hatched area surrounded by a curve that has been shifted by 0.6 in parallel.

The buffer capacity is preferably adjusted by adding a buffer. As the buffer, it is preferable to use bicarbonate, ammonium salt, acetate, phosphate and the like.
More preferably, its sodium salt or potassium salt is used. These salts may be used in combination. When used in combination, a combination of sodium hydrogen carbonate and potassium hydrogen carbonate is preferred. The concentration of bicarbonate or the like in the preparation control serum is preferably 20 to 40.
Concentrations in the mM range.

The buffer has a pKa of 2.76 to 4.7.
6 and 9.33 to 11.33 (p of carbonic acid).
Organic compounds in Ka) can also be used. Preferably, 6-aminocaproic acid, β-alanine, lysine,
N-alanylglycine, 3-methyl-6-phenyl-1
H, 8H-piteridine-2,4,7-trione, (S)
-3,6-diaminohexanecarboxylic acid, N, N'-bis (2-aminoethyl) ethane-1,2-diamine, and the like. Particularly preferred is 6-aminocaproic acid. The concentration of 6-aminocaproic acid in the preparation control serum is preferably in the range of 40 to 60 mM. More preferably, the concentration is in the range of 45 to 55 mM.

[0020] The method for preparing the controlled serum can be applied to commercially available albumin such as human serum albumin, bovine serum albumin, etc. to obtain a controlled serum. As a buffer added to the serum albumins, bicarbonate or 6-
It is preferred to use aminocaproic acid. More preferably, bicarbonates are used.

In dry chemistry, the difference between the value measured using the conventional control serum and the value measured using the fresh human serum is determined by using the adjusted control serum of the present invention instead of the conventional control serum. Can be smaller. In addition, by using the adjusted control serum of the present invention,
The difference between the measured values in the dry chemistry and wet chemistry measurement methods can also be reduced.

[0022] The control serum of the present invention is prepared from a sample (for example,
Glucose, uric acid, BUN (urea nitrogen) in whole blood, plasma, serum, urine, feces, saliva, lymph, body fluids such as cerebrospinal fluid,
Creatinine, calcium, oxalic acid, protein, lipoprotein (LDL, HDL), cholesterol, triglyceride (neutral fat), free fatty acid, ketone body, bilirubin,
Urobrinogen, nitrite, ascorbic acid, hemoglobin, myoglobin, leukocyte, GOT, GPT, AL
It is applicable to detection of P (alkaline phosphatase), γ-GT and the like.

[0023]

EXAMPLES [Example 1] Heparin and disodium ethylenediamine-tetraacetate (ED
TA.2Na), blood was collected from humans using a blood collection tube containing sodium fluoride, and human fresh plasma (2)-
(5) was obtained. Moreover, human fresh serum from human blood (1)
I got Each sample (1 mL) was added to a 1N aqueous hydrochloric acid solution (1
0, 20, 30, 40, 50 μL) and 1N aqueous sodium hydroxide solution (10, 20, 30, 40, 50 μL)
The titration was performed using. The results of these pH titrations are shown in FIG. Here,-□-indicates a pH titration curve of human fresh serum (1),-△-indicates a pH titration curve of human fresh plasma using heparin (2), and-×-indicates a human fresh plasma (3) using heparin. ),-*-Is the pH titration curve of human fresh plasma (4) using EDTA · 2Na,-○-is the pH titration curve of human fresh plasma (5) using sodium fluoride, and- ..-Represents a pH titration curve obtained by averaging these five values. The pH titration curve was obtained from the average titration curve of human fresh serum and human fresh plasma,
Hereinafter, it is referred to as a pH titration curve (S) of human fresh serum. pH
FIG. 1 shows the titration curve (S) as a theoretical quadratic equation by calculation.

[Example 2] A sample prepared by dissolving control serum A (serum obtained by freeze-drying human serum subjected to defibrin treatment) in 1 mL of distilled water, and a sample prepared by dissolving control serum A in 1 mL of 24 mM sodium hydrogencarbonate aqueous solution (control serum) A ')
With a 1N aqueous hydrochloric acid solution (10, 20, 30, 4
0, 50 μL) and a 1N aqueous sodium hydroxide solution (equal volume). Next, the control serum A was mixed with an aqueous solution 1 of a 1N aqueous hydrochloric acid solution and a 24 mM aqueous sodium hydroxide solution.
The sample dissolved in mL (referred to as control serum A ") was titrated in the same manner as described above. The results of the pH titration are shown in Fig. 3. The black squares indicate the control serum A. The pH titration curve, -closed triangle-, indicates the pH of control serum A '.
The titration curve, -x- indicates the pH titration curve of the control serum A ", and -...- indicates the pH titration curve (S).

FIG. 3 shows that the pH titration curves of the control serum A ′ and the control serum A ″ were both pH titration curves (S).
Was found to be contained within the range of pH 0.6 (shaded area). Therefore, by adding a 24 mM aqueous sodium hydrogen carbonate solution or a mixed aqueous solution of a 1N hydrochloric acid aqueous solution and a 4 mM sodium hydroxide aqueous solution to the control serum A, the buffer capacity of the control serum A can be made closer to that of human fresh serum. did it.

[Example 3] Control serum A was treated with 50 mM 6
-A sample (control serum A ^# ) dissolved in 1 mL of an aminocaproic acid aqueous solution was added to a 1N aqueous hydrochloric acid solution (10, 20, 30, 4).
0, 50 μL) and a 1N aqueous sodium hydroxide solution (equal volume). The pH titration curve is shown in FIG. However,
-A black square indicates a pH titration curve of the control serum A (same as that obtained in Example 2), a black triangle indicates a pH titration curve of Example 3, and -...- indicate a pH titration. Represents the curve (S).

From FIG. 4, the pH titration curve of the control serum A ^# prepared by adding the 6-aminocaproic acid aqueous solution to the control serum A is included in the pH titration curve (S) within the range of pH 0.6 (shaded area). It turned out to be. Therefore, control serum A
By adding 6-aminocaproic acid to
The buffer capacity of the control serum A was able to approach the buffer capacity of human fresh serum.

Example 4 A sample obtained by dissolving control serum B (serum obtained by adding human CKMB to human serum subjected to defibrin treatment and delipidation treatment and freeze-dried) in 1 mL of distilled water, control serum B was treated with 25 mM carbonate Sodium hydrogen solution 1
The sample (control serum B ′) dissolved in mL was
Titration was performed with an aqueous solution of N hydrochloric acid (10, 20, 30, 40, 50 μL) and an aqueous solution of 1N sodium hydroxide (the same amount). Here, CKMB is a kind of creatine kinase isozyme and is mainly derived from myocardium. pH
FIG. 5 shows the titration results. Here, -solid squares indicate the pH titration curve of control serum B, -solid triangles indicate the titration curve of control serum B ', and-... Indicate the pH titration curve (S).
Represents

FIG. 5 shows that the pH titration curve of the control serum B ′ prepared by adding an aqueous solution of sodium hydrogen carbonate to the control serum B is included in the pH titration curve (S) within the range of pH 0.6 (shaded area). I understood that.

Example 5 As a sample, CKMB in each sample was measured by dry chemistry and wet chemistry using samples obtained by dissolving the control serum B and the control serum B ′ in 1 mL of distilled water. The former was performed using Fuji Dry Chem Slide-CKMB (manufactured by Fuji Photo Film Co., Ltd.). The latter was carried out using a Merck Auto CKMB (manufactured by Merck) and a 7170 manufactured by Hitachi, Ltd. The results are shown in Table 1 below.

[0031]

[Table 1] Table 1 ────────────────────────────────── Sample Measured value in liquid method in dry method Difference CKMB value (U / L) CKMB value (U / L) (U / L) ────────────────────────────── ──── Control serum B 288 266 22 Control serum B '273 260 13 ───────────────────────────────── ─

From Table 1, it was found that the difference between the measured values in the dry chemistry and the wet chemistry was reduced by adding the aqueous solution of sodium hydrogen carbonate to the control serum B.

Example 6 Control serum C (serum obtained by adding magnesium chloride to defibrin-treated human serum and freeze-dried) was dissolved in 1 mL of distilled water. Control serum C was dissolved in 1 mL of a 30 mM sodium hydrogencarbonate aqueous solution. The dissolved sample (control serum C ′) was titrated with a 1N aqueous hydrochloric acid solution (10, 20, 30, 40, 50 μL) and a 1N aqueous sodium hydroxide solution (the same amount). FIG. 6 shows the pH titration results. However, the black squares represent the control serum C
PH-titration curve of-, filled triangle-indicates p of control serum C '
The H titration curve, and -...- represent the pH titration curve (S).

As shown in FIG. 6, the pH titration curve of the control serum C ′ prepared by adding the aqueous solution of sodium hydrogen carbonate to the control serum C is included in the pH titration curve (S) within the range of pH 0.6 (shaded area). I understood that.

Example 7 Using a sample obtained by dissolving the above-mentioned control serum C and control serum C ′ in 1 mL of distilled water, magnesium ions in each sample were measured by dry chemistry and wet chemistry. .
The former was performed using Fuji Dry Chem Slide-Magnesium (manufactured by Fuji Photo Film Co., Ltd.). The latter was carried out with 7170 manufactured by Hitachi, Ltd. using Diamond Color-Magnesium (manufactured by Ono Pharmaceutical Co., Ltd.). The results are shown in Table 2 below.

[0036]

[Table 2] Table 2 ────────────────────────────────── Sample Measured value in dry method and liquid method Difference Mg ²⁺ amount (mg / dL) Mg ²⁺ amount (mg / dL) (mg / dL) ────────────────────────── {Control serum C 5.0 6.7-1.7 Control serum C '6.4 6.3 0.1} ──────────────────

From Table 2, it was found that the difference between the measured values of the dry chemistry and the wet chemistry was reduced by using the preparation control serum C ′.

Example 8 Control serum D (freeze-dried human serum subjected to defibrin treatment for multi-item measurement control, QP-H, manufactured by Fuji Photo Film Co., Ltd.) was distilled water 1
The sample (control serum D ′) dissolved in 1 mL of a 25 mM sodium hydrogencarbonate aqueous solution was dissolved in a 1N hydrochloric acid aqueous solution (10, 20, 3).
0, 40, 50 μL) and 1N aqueous sodium hydroxide solution (equal volume). FIG. 7 shows the results of the pH titration.
However, the black squares represent the pH titration curve of the control serum D,
-A black triangle indicates a pH titration curve of the control serum D ', and -...- indicates a pH titration curve (S).

According to FIG. 7, the pH titration curve of the control serum D ′ prepared by adding the aqueous solution of sodium hydrogen carbonate to the control serum D is included in the range of pH 0.6 (the shaded area) of the pH titration curve (S). I understood.

Example 9 As a sample, a sample obtained by dissolving the above-mentioned control serum D and control serum D ′ in 1 mL of distilled water was used, and AMYL (amylase) in each sample was used.
Each item of ALP (alkaline phosphatase) and UA (uric acid) was measured by dry chemistry and wet chemistry. For the former, Fuji Dry Chem Slide (Fuji Photo Film Co., Ltd.)
Was carried out using For the latter, amylase II-HA Test Wako (Wako Pure Chemical Industries, Ltd.)
), Alkaline Phosphor HA Test Wako (manufactured by the same company), AUTOCERA UA-2 (Daiichi Pure Chemical Co., Ltd.)
Manufactured by Hitachi, Ltd.). The results are shown in Table 3 below.

[0041]

[Table 3]

From Table 3, it was found that the difference between the measured values of dry chemistry and wet chemistry was reduced by adding an aqueous solution of sodium bicarbonate to the control serum D. In particular, this effect was remarkably observed in the measurement of amylase.

Example 10 The above-mentioned control serum D was 50 m
M 6-aminocaproic acid aqueous solution (pKa 4.38, 1
0.80) The sample (control serum D ″) dissolved in 1 mL was
1N hydrochloric acid aqueous solution (10, 20, 30, 40, 50 μL)
And a 1N aqueous sodium hydroxide solution (same amount). FIG. 8 shows the pH titration results. However,-black square-
Is a graph showing the pH titration curve of the control serum D, -black triangles are graphs showing the pH titration curve of Example 10, and -...- are pH titration curves (S).

As shown in FIG. 8, the pH titration curve of the control serum D "obtained by adding the 6-aminocaproic acid aqueous solution to the control serum D is included in the pH titration curve (S) within the range of pH 0.6 (shaded area). It turned out to be.

[Example 10] As samples, AMYL (amylase) and GPT (glutamate-pyruvate transaminase) in each of the samples were prepared by dissolving the control serum D and the control serum D ″ in 1 mL of distilled water. The measurement was performed by dry chemistry and wet chemistry for each of the above items, and the former was performed using Fuji Dry Chem Slide (manufactured by Fuji Photo Film Co., Ltd.) for each measurement item. HA Test Wako (manufactured by Wako Pure Chemical Industries, Ltd.) and Autocera GPT-2 (manufactured by Daiichi Pure Chemicals Co., Ltd.) were used and performed by Hitachi, Ltd. 7170. The results are shown in Table 4 below. .

[0046]

[Table 4] Table 4 ────────────────────────────────── Measurement items Sample Dry method Liquid method Measured values Difference (U / L) (U / L) (U / L) ────────────────────────────────── AMYL Controlled Serum D 353 321 32 Controlled Serum D "310 329-19 GPT Controlled Serum D 83 749 Controlled Serum D" 80 773 ───────────────────── ─────────────

From Table 4, it was found that the addition of an aqueous solution of 6-aminocaproic acid to the control serum D reduced the difference in measured values between dry chemistry and wet chemistry.

Example 11 Human serum albumin (Al
bumin Human Fraction VPoW
der (manufactured by Sigma) was dissolved in distilled water to make 1 mL of an aqueous solution (total protein concentration: 7.3 g / dL), and human serum albumin was added to a 30 mM aqueous sodium hydrogen carbonate solution to make 1 mL. (Control Serum H) was added to a 1N aqueous hydrochloric acid solution (10, 20, 30, 40, 50, respectively).
μL) and a 1N aqueous sodium hydroxide solution (same volume). FIG. 9 shows the pH titration results. However,-the black square-is the pH titration curve of the human serum albumin aqueous solution,
-A black triangle indicates a pH titration curve of the control serum H, and -...- indicates a pH titration curve (S).

FIG. 9 shows that the pH titration curve of the control serum H ′ prepared by adding an aqueous solution of sodium hydrogen carbonate to human serum albumin is included in the pH titration curve (S) within the range of pH 0.6 (shaded area). I understood.

Example 12 Bovine Serum Albumin (Alb
umin, Bovine Initial Fract
aqueous solution of ionation by Heat Shock (manufactured by Sigma) in 1 mL of distilled water (7.
5% by weight) and a sample (control serum I) obtained by dissolving bovine serum albumin in 1 mL of a mixed aqueous solution of a 22 mM aqueous sodium bicarbonate solution and a 4 mM aqueous potassium bicarbonate solution (control serum I). 40, 5
0 μL) and a 1N aqueous sodium hydroxide solution (equal volume). The pH titration results are shown in FIG. Here, -solid squares indicate the pH titration curve of bovine serum albumin aqueous solution, -solid triangles indicate the pH titration curve of control serum I, and -...- indicate the pH titration curve (S).

FIG. 10 shows that the pH titration curve of the control serum I prepared by adding an aqueous solution of sodium bicarbonate and an aqueous solution of potassium bicarbonate to an aqueous solution of bovine serum albumin is within the range of pH 0.6 of the pH titration curve (S) (shaded line). Region).

Example 13 (1) Measurement of Sodium Ion Content by Ion Selective Electrode Method and Flame Photometry Control serum I ′ was obtained by adding bovine serum albumin powder to a 0.9% aqueous sodium chloride solution at 7.5% by weight. It melt | dissolved so that it might be obtained. The control serum I ″ was prepared by adding bovine serum albumin powder (8.0 g) to a 22 mM aqueous sodium hydrogen carbonate solution.
It was obtained by dissolving in a mixed aqueous solution (100 mL) of a 4 mM aqueous solution of potassium bicarbonate-aqueous solution of 101 mM sodium chloride. In addition, sodium chloride was added in order to make the concentration measurable with the used equipment. The amount of sodium ion in the control serum I 'and the control serum I "was measured by using Fuji Drychem electrolyte slide (Fuji Photo Film Co., Ltd.)
And a flame photometer (Hitachi 710, manufactured by Hitachi, Ltd.) (Table 5).

[0053]

[Table 5] Table 5 ────────────────────────────────── Sample Ion-selective electrode method Flame photometry Measurement value difference (milli-equivalent / L) (milli-equivalent / L) (milli-equivalent / L) ───── Controlled serum I '165 158 7 Controlled serum I "137 136 1 ─────────────────────────────── ───

From Table 5, it was found that the addition of the aqueous sodium hydrogencarbonate solution and the aqueous potassium hydrogencarbonate solution reduced the difference between the values measured by the two methods described above.

(2) Measurement of Chloride Ion by Ion-Selective Electrode Method and Coulometric Titration Using control serum I ′ and control serum I ″ prepared in (1), the amount of chloride ion in these samples was determined. Fuji drychem electrolyte slides (Fuji Photo Film Co., Ltd.)
Manufactured by Hitachi, Ltd.) and coulometric titration (Hitachi 710, manufactured by Hitachi, Ltd.) (Table 6).

[0056]

[Table 6] Table 6 試 料 Sample Ion-selective electrode method Flame photometry Measurement value difference (milli-equivalent / L) (milli-equivalent / L) (milli-equivalent / L) ───── Controlled serum I '134 143-9 Controlled serum I "100 101 -1 ───────────────────────────── ─────

From Table 6, it was found that the same effects as those shown in Table 5 were observed.

[0058]

According to the present invention, the adjusted control serum containing a buffer such as bicarbonate or 6-aminocaproic acid in the existing control serum is a measurement value obtained when the existing control serum was used instead of the fresh human serum. Can be reduced. Therefore, if the adjusted serum is used for clinical examination, it is possible to always ensure the same reactivity as fresh human serum. In addition, since the control serum can reduce the difference between the measured values caused by the difference in the measurement method between the dry chemistry and the wet chemistry, it can be used regardless of the measurement method.

[Brief description of the drawings]

FIG. 1 shows a pH titration curve of human fresh serum and a pH-regulated region (hatched region) of the serum of the present invention.

FIG. 2 is a pH titration curve of human fresh serum, a pH titration curve of human fresh plasma, and a pH titration curve obtained by averaging the titration values of human fresh serum and human fresh plasma.

FIG. 3 is a pH titration curve of Example 2.

FIG. 4 is a pH titration curve of Example 3.

FIG. 5 is a pH titration curve of Example 4.

FIG. 6 is a pH titration curve of Example 6.

FIG. 7 is a pH titration curve of Example 8.

FIG. 8 is a pH titration curve of Example 10.

FIG. 9 is a pH titration curve of Example 11.

FIG. 10 is a pH titration curve of Example 12.

Claims (5)

[Claims] 1. A control serum containing a buffer, wherein 1 mL of a 1N hydrochloric acid aqueous solution is used for 1 mL of the control serum.
L, 30 [mu] L, 40 [mu] L, Y _A are the respective pH values when titrated with 50μL is, in each titration conditions in the range of pH4 to 7.7, the following ^{_{formula: 0.0002 × (X A) 2}} - 0.0628 × (X _A ) +
7.0521 ≦ Y _A ≦ 0.0002 × (X _A ) ² -0.
Wherein, X _A represents a drip quantitative] 0628 × (X _A) +8.2521 satisfied, and the management serum 1 N sodium hydroxide solution for 1 mL 1
When Y _B , which is the pH value when titrated with 0 μL, 20 μL, 30 μL, 40 μL, and 50 μL, is in the range of pH 7.7 to 11 under each titration condition, the following formula: −0.0009 × (X _B ) ² + 0.0971 × (X _B )
+ 7.1521 ≦ Y _B ≦ −0.0009 × (X _B ) ² +
0.0971 × (X _B ) +8.3521 wherein X _B represents the titer. 2. The controlled serum according to claim 1, wherein the control serum containing a buffer is an aqueous human serum albumin solution or an animal serum albumin aqueous solution containing a buffer. 3. The serum according to claim 1, wherein the buffer is a bicarbonate or an ammonium salt. 4. The buffer has a pKa of 2.76 to 4.7.
The controlled serum according to claim 1, wherein the serum is an organic compound in the range of 6. and 9.33 to 11.33. 5. The regulated serum according to claim 4, wherein the organic compound is 6-aminocaproic acid.