阅读说明：本技术 样本稀释液及其制备方法和消除新鲜样本检测异常的免疫分析方法 (Sample diluent, preparation method thereof and immunoassay method for eliminating fresh sample detection abnormality ) 是由 冯志山 黄巍 靳增明 张玉娇 张学东 于 2021-09-09 设计创作，主要内容包括：本发明涉及体外诊断技术领域,特别涉及样本稀释液及其制备方法和消除新鲜样本检测异常的免疫分析方法。该样本稀释液包括组分A、组分B和生物缓冲液；组分A为硫辛酸或二氢硫辛酸；组分B为硫酸葡聚糖或其盐。本发明将硫辛酸和硫酸葡聚糖组合,并将其应用于免疫临床检测中,避免因样本新鲜程度不同所导致的检测结果的异常。本稀释液可以有效防止新鲜样本中的干扰,能够消除样本中含有的补体及纤维蛋白等主要干扰物质。本稀释液能降低免疫分析中的非特异性反应,从而提高试剂的准确度及精密性。本稀释液制备方法简单,具备安全性和环境友好性。(The invention relates to the technical field of in-vitro diagnosis, in particular to a sample diluent, a preparation method thereof and an immunoassay method for eliminating the detection abnormality of a fresh sample. The sample diluent comprises a component A, a component B and a biological buffer solution; the component A is lipoic acid or dihydrolipoic acid; the component B is dextran sulfate or salt thereof. The invention combines the lipoic acid and the dextran sulfate and applies the lipoic acid and the dextran sulfate to the clinical immunoassay, thereby avoiding the abnormality of the test result caused by different sample freshness degrees. The diluent can effectively prevent interference in a fresh sample and eliminate main interference substances such as complement, fibrin and the like contained in the sample. The diluent can reduce nonspecific reaction in immunoassay, thereby improving the accuracy and precision of the reagent. The diluent is simple in preparation method and has safety and environmental friendliness.)

1. A sample diluent, wherein the sample diluent comprises a component a, a component B, and a biological buffer; the component A is lipoic acid or dihydrolipoic acid; the component B is dextran sulfate or salt thereof.

2. The sample diluent according to claim 1, wherein the concentration of the component A in the sample diluent is 0.05-5% by mass, and the concentration of the component B in the sample diluent is 0.01-5% by mass.

3. The sample diluent according to claim 1, wherein the concentration of the component A in the sample diluent is 0.05-2.0% by mass, and the concentration of the component B in the sample diluent is 0.1-3.0% by mass.

4. The sample diluent according to claim 1, wherein the concentration of the component A in the sample diluent is 0.05-0.5% by mass, and the concentration of the component B in the sample diluent is 0.1-2.5% by mass.

5. The sample diluent of claim 1, wherein the biological buffer is selected from one or more of phosphate buffer, HEPES buffer, MOPS buffer, Tris-HCl buffer, MES buffer.

6. The sample diluent according to claim 1, wherein the concentration of the biological buffer is 0.01 to 1.0 mol/L.

7. The sample diluent according to claim 1, wherein the pH value of the sample diluent is 6 to 10.

8. The sample diluent according to any one of claims 1 to 7, wherein the dextran sulfate or a salt thereof has a molecular weight of 3 to 1000 kDa.

9. The method for preparing a sample diluent according to any one of claims 1 to 8, wherein the components A and B are dissolved in a biological buffer and the pH is adjusted.

10. An immunoassay method for eliminating the detection abnormality of a fresh sample, characterized in that a sample to be tested is treated with the sample diluent according to any one of claims 1 to 8 in an immunoassay method based on antigen-antibody binding.

Technical Field

The invention relates to the technical field of in-vitro diagnosis, in particular to a sample diluent, a preparation method thereof and an immunoassay method for eliminating the detection abnormality of a fresh sample.

Background

Common interference in immune response comprises endogenous and exogenous interference, and common endogenous interference factors comprise complement, rheumatoid factor RF, autoantibodies, heterophilic antibodies and the like; the exogenous interference factors mainly include lipemia, bacterial infection, hemolysis, high bilirubin, fibrin, etc.

Complement is a group of enzymatically active proteins present in human or vertebrate serum and interstitial fluid. It is called complement because it is a necessary complement for the antibody to exert cytolytic action. The intrinsic components of the complement system are produced by macrophages, hepatocytes, small intestinal epithelial cells, splenocytes, and the like. Activation of complement can cause unwanted immune responses with aberrant interfering outcomes.

Fibrin is converted from fibrinogen, which is insoluble in water. The interference of serum fibrin is usually caused by blood coagulation insufficiency, and a part of fibrinogen remains in the separated serum, and fibrin is generated during placement or detection, so that the antigen-antibody reaction is interfered, and the detection result is abnormal.

Currently, various methods are available to reduce the interference caused by complement and fibrin. Such as: application number CN110849981A discloses a sample pretreatment solution for vitamin D quantitative detection, which comprises normal saline, dextran sulfate sodium salt and a beta-heterophilic blocking agent, wherein the dextran sulfate sodium salt and the beta-heterophilic antibody are mainly used for separating 25-hydroxyvitamin D and binding protein. Application No. 201911044431.7 discloses a chemiluminescence method kit formula for eliminating fibrinogen interference, wherein a sample diluent of the chemiluminescence method contains plasmin. Application No. 202010522371.1 relates to a device for separating high density lipoprotein in serum, wherein the low density lipoprotein blocking reagent is one or more of dextran sulfate and its salt, magnesium phosphotungstate, and polyethylene glycol 20000.

However, the sample diluent has limited anti-interference effect after the pretreatment of the sample.

Disclosure of Invention

In view of the above, the present invention provides a sample diluent, a preparation method thereof, and an immunoassay method for eliminating the detection abnormality of a fresh sample. The sample diluent overcomes the defect of abnormal detection result of a fresh sample in the prior immunity technology, has simple operation, obvious anti-interference effect and better stability, and is suitable for conventionally detecting human serum and plasma samples.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a sample diluent, which comprises a component A, a component B and a biological buffer solution; the component A is lipoic acid or dihydrolipoic acid; the component B is dextran sulfate or salt thereof.

The invention provides a composition contained in a diluent for eliminating the detection difference of new and old samples, which can fully avoid complement activation and further eliminate the interference effect of complement. The diluent for eliminating the abnormal detection of the fresh sample and the application thereof are characterized in that the lipoic acid and the dextran sulfate composition are simultaneously introduced into the diluent for eliminating the abnormal interference in the fresh sample, and full research shows that the lipoic acid and the dextran sulfate contained in the diluent can jointly eliminate the interference of complement of the fresh sample and can jointly promote the degradation of fibrin in the sample. The diluent can eliminate abnormal results caused by overhigh complement content and fibrin in a fresh sample, avoid the influence of the complement and the fibrin on the determination of markers in human serum and plasma, and is favorable for carrying out chemiluminescence reaction and washing magnetic particles, thereby ensuring the accuracy of an immunity measurement result.

Wherein, the main component of the composition in the diluent of the invention is dextran sulfate which can enhance the action capability of a C1 inhibitor and inhibit C3 and C4, thereby inhibiting the classical pathway of complement activation; the combination of the H factor and the C3b is promoted and strengthened, so that the alternative pathway C3 invertase can not be assembled smoothly, and the activation of complement can be inhibited from the alternative pathway; in addition, the kit can also influence the lectin activation pathway of complement, influence the effect of complement activation from multiple aspects, and play a certain role in eliminating the abnormal interference of complement on the detection of a fresh sample. The lipoic acid component of the composition contained in the diluent can fully complex metal ions in a complement activation pathway, fully chelates calcium ions related to a classical activation pathway, magnesium ions related to an MBL activation pathway and a bypass pathway, plays a powerful complement elimination capacity, plays a special role of complementary co-entering with dextran sulfate in the diluent, and jointly eliminates a sample abnormality detection result caused by complement, and the introduction of the lipoic acid improves the complement inhibition rate of the dextran sulfate in the diluent on the complement, so that an immune reagent can more accurately detect a fresh sample, and the abnormality of the fresh sample detection result caused by the complement is avoided.

The dextran sulfate in the diluent can enhance the activity of plasminogen activator by inducing the dissolution of human plasma endogenous fibrin, thereby improving the action of plasmin and reducing the abnormal interference phenomenon caused by fibrin; the lipoic acid can promote the average level of the plasminogen activator to be remarkably increased, and the lipoic acid and the dextran sulfate play a synergistic and complementary role to jointly promote the elimination of the influence of fibrin interference in a fresh sample, so that the abnormality of the detection result of the fresh sample is avoided.

Preferably, the mass percentage concentration of the component A in the sample diluent is 0.05-5%, and the mass percentage concentration of the component B in the sample diluent is 0.01-5%.

Preferably, the mass percentage concentration of the component A in the sample diluent is 0.05-2.0%, and the mass percentage concentration of the component B in the sample diluent is 0.1-3.0%.

More preferably, the mass percentage concentration of the component A in the sample diluent is 0.05-0.5%, and the mass percentage concentration of the component B in the sample diluent is 0.1-2.5%.

In the present invention, the biological buffer is selected from one or more of phosphate buffer, HEPES buffer, MOPS buffer, Tris-HCl buffer, MES buffer, but not limited thereto.

Preferably, the concentration of the biological buffer solution is 0.01-1.0 mol/L.

Preferably, the pH value of the sample diluent is 6-10.

Preferably, the pH value of the sample diluent is 7.5-9.0.

Preferably, the dextran sulfate or the salt thereof has a molecular weight of 3 to 1000 kDa.

The invention also provides a preparation method of the sample diluent, which is to dissolve the component A and the component B in a biological buffer solution and adjust the pH value.

The invention also provides an immunoassay method for eliminating the detection abnormality of the fresh sample, and in the immunoassay method based on antigen-antibody combination, the sample diluent is adopted to process the sample to be detected.

In the present invention, the sample to be tested is serum or plasma. The diluent can be used for detecting various clinical markers in serum and plasma samples.

The invention provides a sample diluent, a preparation method thereof and an immunoassay method for eliminating the detection abnormality of a fresh sample. The sample diluent comprises a component A, a component B and a biological buffer solution; the component A is lipoic acid or dihydrolipoic acid; the component B is dextran sulfate or salt thereof. The invention has the technical effects that:

the invention combines the lipoic acid and the dextran sulfate and applies the lipoic acid and the dextran sulfate to the clinical immunoassay, thereby avoiding the abnormality of the test result caused by different sample freshness degrees. The diluent can effectively prevent interference in a fresh sample and eliminate main interference substances such as complement, fibrin and the like contained in the sample. The diluent can reduce nonspecific reaction in immunoassay, thereby improving the accuracy and precision of the reagent. The diluent is simple in preparation method and has safety and environmental friendliness;

the lipoic acid in the diluent can fully complex various metal ions of a complement activation pathway, and assists glucan sulfate in the diluent to inhibit and eliminate a complement system, so that the abnormality of a fresh sample detection result caused by complement interference is avoided; the activation of a plasmin system is promoted by the dextran sulfate and the lipoic acid together, so that the removal capacity of the fibrin is improved, the abnormality of a fresh sample detection result caused by the interference of the fibrin is avoided, and the authenticity and reliability of the detection result are guaranteed.

Detailed Description

The invention discloses a sample diluent, a preparation method thereof and an immunoassay method for eliminating the detection abnormality of a fresh sample, and a person skilled in the art can realize the method by properly improving process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The reagents or apparatus used in the present invention are commercially available. Wherein lipoic acid is available from sigma; dextran sulfate and salts thereof are available from Sigma and have a molecular weight of 3-1000 kDa.

The invention is further illustrated by the following examples:

example 1

First, diluent formula and preparation method thereof

First, a diluent of the present invention is prepared, wherein the diluent comprises 0.05% by mass of lipoic acid, 0.1% by mass of dextran sulfate and a PBS buffer. The preparation method comprises the following steps: the lipoic acid and the dextran sulfate in the proportion are fully dissolved in 0.1mol/L PBS solution, and are fully and uniformly mixed, and then the pH is adjusted to 7.5 for experimental study.

Control dilution 1 was 0.05% lipoic acid only and PBS buffer; control dilution 2 was 0.1% dextran sulfate alone and PBS buffer. Control dilution 1 and control dilution 2 were prepared as described above.

Second, detection method

The method for detecting the content of 25-hydroxy vitamin D in a human serum or plasma sample by using the diluent prepared by the invention specifically comprises the following steps:

1. preparing magnetic particle suspension coated with anti-25-hydroxyvitamin D antibody;

2. preparing a gradient calibrator containing 25-hydroxy vitamin D antigen;

3. preparing 25-hydroxy vitamin D marked by horseradish peroxidase;

4. the experimental group diluent and the control group diluent were prepared according to the method of step one in this example;

5. selecting 20 parts of the fresh clinical samples collected and processed according to the correct medical technology on the same day, and detecting the content of 25 hydroxy vitamin D;

6. respectively adding a certain amount of sample to be detected and a certain amount of calibrator into the reaction cups; adding a certain amount of uniformly mixed magnetic particle suspension; adding a certain amount of experimental group diluent or control group diluent; adding a proper amount of enzyme conjugate, uniformly mixing, and then incubating at 37 ℃; separating and washing the magnetic beads by using a magnetic separation device; vibrating and uniformly mixing the magnetic beads, and adding a luminescent substrate for light-resistant reaction;

7. the luminescence intensity was measured using a chemiluminescence immunoassay analyzer.

Third, clinical comparison study

20 parts of clinical samples freshly collected on the same day are subjected to an experiment by a chemiluminescence method and a liquid phase tandem mass spectrometry to detect 25-hydroxyvitamin D, and as shown in Table 1, compared with the mass spectrometry, an experiment group containing 0.05% of lipoic acid and 0.1% of dextran sulfate diluent does not have an abnormal result that the concentration deviation between the samples exceeds 10%;

the detection result of the group of the control diluent 1 shows that the whole concentration of 20 fresh samples is 98.7 percent higher than that of the mass spectrum;

the test results of the control diluent 2 group showed that 20 fresh samples showed an overall 96.3% higher mass concentration compared to the mass spectral concentration.

TABLE 1

Example 2

First, diluent formula and preparation method thereof

Firstly, the buffer solution of the invention is prepared, wherein the buffer solution comprises 0.5 percent of lipoic acid and 2.5 percent of dextran sulfate and MOPS buffer solution by mass ratio. The preparation method comprises the following steps: the lipoic acid and the dextran sulfate in the proportion are fully dissolved in 0.5mol/L MOPS buffer solution, and are fully and uniformly mixed, and then the pH value is adjusted to 9.0 for experimental study.

Control diluent 1 was lipoic acid and MOPS buffer only 0.5%; control dilution 2 was 2.5% dextran sulfate only and MOPS buffer. Control dilution 1 and control dilution 2 were prepared as described above.

Second, detection method

The method for detecting the content of the antitriothyronine in the human serum or plasma sample by using the diluent prepared by the invention specifically comprises the following steps:

1. preparing magnetic particle suspension coated with antitriothyronine antigen;

2. preparing a gradient calibrator containing an anti-triiodothyronine antigen;

3. preparing an anti-triiodothyronine antibody marked by horseradish peroxidase;

4. the experimental group diluent and the control group diluent were prepared according to the method of step one in this example;

5. selecting 20 fresh clinical samples collected and processed according to a correct medical technology on the same day, and detecting the content of the thyronine diiodo;

6. respectively adding a certain amount of sample to be detected and a certain amount of calibrator into the reaction cups; adding a certain amount of experimental group diluent or control group diluent; adding a certain amount of uniformly mixed magnetic particle suspension; adding a proper amount of enzyme conjugate, uniformly mixing, and then incubating at 37 ℃; separating and washing the magnetic beads by using a magnetic separation device; vibrating and uniformly mixing the magnetic beads, and adding a luminescent substrate for light-resistant reaction;

7. the luminescence intensity was measured using a chemiluminescence immunoassay analyzer.

Third, clinical comparison study

20 parts of clinical samples freshly collected on the same day are subjected to an experiment by a chemiluminescence method and a liquid phase tandem mass spectrometry simultaneously to detect the triiodothyronine, and as shown in table 2, compared with the mass spectrometry, an experiment group containing 0.5% of lipoic acid and 2.5% of dextran sulfate diluent does not have an abnormal result that the concentration deviation between the samples exceeds 10%;

the detection result of the group of the control diluent 1 shows that the overall average of 20 fresh samples is higher by 68.1 percent compared with the mass spectrum concentration;

the test results of the control dilution 2 group showed that 20 fresh samples averaged 75.8% higher overall than the mass spectral concentration.

TABLE 2

Example 3

First, diluent formula and preparation method thereof

Firstly, the buffer solution of the invention is prepared, wherein the buffer solution comprises 0.25 percent of lipoic acid and 0.75 percent of dextran sulfate and Tris-HCl buffer solution by mass ratio. The preparation method comprises the following steps: the lipoic acid and the dextran sulfate in the proportion are fully dissolved in 0.1mol/L Tris-HCl buffer solution, and are fully and uniformly mixed, and then the pH value is adjusted to 8.5 for experimental study.

Control diluent 1 was 0.25% lipoic acid and Tris-HCl buffer only; control dilution 2 was 0.75% dextran sulfate and Tris-HCl buffer only. Control dilution 1 and control dilution 2 were prepared as described above.

Second, detection method

The method for detecting the content of osteocalcin in a human serum or plasma sample by using the diluent prepared by the invention specifically comprises the following steps:

1. preparing a coated anti-osteocalcin antibody magnetic particle suspension;

2. preparing a gradient calibrator containing osteocalcin;

3. preparing an anti-osteocalcin antibody marked by horseradish peroxidase;

4. the experimental group diluent and the control group diluent were prepared according to the method of step one in this example;

5. selecting 20 fresh clinical samples collected and processed according to a correct medical technology on the same day, and detecting the content of osteocalcin;

6. respectively adding a certain amount of sample to be detected and a certain amount of calibrator into the reaction cups; adding a certain amount of experimental group diluent or control group diluent; adding a certain amount of uniformly mixed magnetic particle suspension; adding a proper amount of enzyme conjugate, uniformly mixing, and then incubating at 37 ℃; separating and washing the magnetic beads by using a magnetic separation device; vibrating and uniformly mixing the magnetic beads, and adding a luminescent substrate for light-resistant reaction;

7. the luminescence intensity was measured using a chemiluminescence immunoassay analyzer.

Third, clinical comparison study

20 parts of clinical samples freshly collected on the same day and a Roche electrochemiluminescence method are used for detecting osteocalcin simultaneously. As shown in table 3, in the test of the 20 samples, the concentration deviation of the test result and the roche measurement result of the test group containing 0.25% by mass of lipoic acid and 0.75% by mass of dextran sulfate diluent is not more than 10%;

the test results of the group of control diluent 1 show that the concentration deviation of 20 fresh samples is over 72.5% compared with the Roche measurement results;

the test results of the control dilution 2 group showed that 20 fresh samples had an overall concentration deviation of more than 59.2% compared to the results of the roche measurement.

TABLE 3

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.