ELISA kit is an experimental diagnostic method with high sensitivity, strong specificity and good reproducibility. Due to its stable reagents, easy storage, easy operation, objective result judgment and other factors, it is suitable for large-scale screening tests and It can be used for the detection of a small number of specimens. It can be used for both qualitative testing and quantitative analysis. It has been widely used in microbiology, parasitology, oncology, and cytokines. There are many influencing factors of ELISA kits, and only by strengthening quality management can the advantages of its methodology be fully utilized.
The personnel training experiment is done by ***, so the inspectors need to be trained to master the technical knowledge of the following aspects of this major:
The basic principle of the inspection project (the principle of ELISA kit);
Clinical significance;
Familiar with testing techniques, understand the links and difficulties that are prone to errors;
Familiar with the performance of detection reagents (including kit composition, coated fragments and their composition);
Familiar with the principle and performance of testing instruments; master the data processing ability and quality control knowledge.
The testing of some special projects, such as anti-HIV, requires special training courses organized by relevant departments.
Quality control before analysis
In 1971, Engvall et al. Applied immunohistochemical EIA technology to clinical testing to develop ELISA kit technology.
Features: Assemble immunoactive substances on the surface of solid phase to form "immunosorbent"
Enzyme-labeled immunologically active substances for signal amplification;
There is a two-step incubation reaction and a second washing process;
The sensitivity and specificity are relatively high.
Limitations: only ng levels can be detected
Poor precision (CV15-20% in batch);
Narrow linear range (one order of magnitude);
There is a "HD-HOOK" effect.
Principle of ELISA kit
There are three basic methods according to the detection purpose and operation steps.
The common method of detecting the antigen (body) by the double antibody (original) sandwich method, using two monoclonal antibodies against two different determinants of the antigen as a solid phase carrier and an enzyme-labeled antibody to detect the antigen in the solution (suitable for antigens of more than two valence , Can not measure small molecule hapten).
The indirect method for detecting antibodies uses enzyme-labeled anti-antibodies (second antibodies) to detect antibodies that have bound to solid-phase antigens.
The competition method detects antigen or small molecule hapten and antibody. Taking the test antigen as an example, the test antigen and the enzyme-labeled antigen compete for binding to the solid-phase antibody. As a result, the more the test-antigen content, the enzyme-label bound to the solid-phase antibody The less antigen, the lighter the color, the two are negatively correlated.
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