Enzyme-linked immunosorbent assay

The enzyme-linked immunosorbent assay is an enzyme-linked immunosorbent assay. It is used to detect the antigen (or antibody) to be tested which is coated in the well of the solid phase plate. That is, the antibody is labeled with an enzyme, and the known antigen or antibody is adsorbed on the surface of the solid phase carrier, and the antigen-antibody reaction is carried out on the surface of the solid phase carrier, and the free component in the liquid phase is washed away by washing, and finally acted on by the enzyme. The color is developed after the substrate to judge the result. The depth of the color reaction is proportional to the amount of the corresponding antibody or antigen in the specimen. This color reaction can be quantitatively determined by an ELISA detector, which combines the sensitivity of the enzyme chemical reaction with the specificity of the antigen-antibody reaction, making the ELISA method a both specific and sensitive detection method. Basic Information Specialist classification: growth and development check classification: immunological examination Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Normal value: no Above normal: negative: normal. Positive: The human body is in a dynamic equilibrium and unhealthy state. Tips: Relax while checking. Normal value The type and proportion of the flora in the body are normal, and the human body is in a state of dynamic balance and health. Clinical significance The enzyme-linked immunosorbent assay is the most widely used technique in enzyme immunoassay. Commonly used ELISA methods include a double antibody sandwich method and an indirect method, the former for detecting macromolecular antigens and the latter for measuring specific antibodies. In terms of parasitic diseases, it is used for serological diagnosis of Plasmodium, Amoeba, Liegemann, Trypanosoma, Schistosomiasis, cysticercosis, Toxoplasma, Schistosomiasis, Liver fluke, Bloodworm, Trichinosis This is important for both doctors and veterinarians. It has been used to detect antibodies against Streptococcus, Salmonella, Brucella, Mycobacterium tuberculosis, Haemophilus, Vibrio cholerae, Neisseria gonorrhoeae, Candida, etc., and can also be used for tetanus antitoxin and Vibrio cholerae antitoxin. The determination and detection of antibodies against rickettsia rickettsia infection can be diagnosed. Rickettsia can also be used to identify closely related species. There are also reports for examining antibodies against Chlamydia psittaci. Influenza virus, mumps virus, measles, rubella, rotavirus, herpes virus, cytomegalovirus, EB virus, adenovirus, enterovirus, encephalitis virus, yellow fever virus, rabies Toxic and poliovirus, etc., are more sensitive than the currently used inspection methods. In immunological diseases, there are tests for the detection of autoimmune diseases and the diagnosis of allergies, such as antibodies against various allergens, DNA antibodies and thyroglobulin antibodies, erythematosus antibodies, and the like. In hygiene, it can be used to detect staphylococcal enterotoxin and salmonella toxin in foods. Positive results may be diseases: acquired bullous epidermolysis, trypanosomiasis, schistosomiasis and hepatobiliary diseases, toxoplasmosis scleritis, Gestman syndrome, neonatal congenital toxoplasmosis, liver fluke, Siberian rickettsia spotted fever, intestinal piriflagellate, tourist diarrhea precautions 1. Substrate: Various enzymes have specificity for the substrate, so the use of different types of enzymes requires different substrates. Once the enzyme conjugate has been determined (eg, AP or HRP), the range of substrates available for selection is very limited. How to select a suitable substrate within the scope of this limited substrate should be selected according to the following conditions: (1) The substrate should be colorless before being catalyzed by the enzyme, and have obvious color after being catalyzed by the enzyme. Change, so that the results can be clearly distinguished; (2) the color is easy to dry and elute; (3) the product after color development is required to be stable, the colored substance produced in the quantitative determination should be soluble; (4) the price Cheap, easy to get and non-toxic. Therefore, for the AP enzyme conjugate, nitrophenyl phosphate is generally used, and the color is orange after color development, and the color is stable. The reaction is terminated with 2 mol/L NaOH, and the OD value can be measured at a wavelength of 403 nm. 2. Detergent and thinner: In order to maximize the amount of antibody specifically bound, the antigen coated in the well of the microplate should be slightly excess. However, during incubation or washing, some of the adsorbed antigen may be washed away from the solid support. Therefore, the protein other than the specific antibody added to the test serum is likely to adsorb to the blank of the original antigen-coated pit, increasing the background color and generating a false positive reaction, which is a factor limiting the specificity of the ELISA. Many scholars have added various protective agents to diluents and detergents to inhibit the competitive adsorption of non-specific proteins. Inspection process The basic method is to adsorb a known antigen or antibody on the surface of a solid phase carrier (polystyrene micro-reaction plate), react the enzyme-labeled antigen-antibody reaction on the surface of the solid phase, and wash the free components in the liquid phase by washing. except. According to the solid phase carrier used in ELISA, it is divided into three types: one is ELISA using polystyrene microplate as carrier, which is the ELISA (microplate ELISA) we usually refer to; the other is using nitrocellulose membrane as carrier. The ELISA is called spot ELISA (Dot-ELISA); the other is ELISA using hydrophobic polyester cloth as a carrier, called cloth ELISA (C-ELISA). In the microplate ELISA, it is further divided into indirect ELISA, double antibody sandwich ELISA, double sandwich ELISA, competition ELISA, blocking ELISA and antibody capture ELISA according to its properties. Not suitable for the crowd There are no special taboos. Adverse reactions and risks There are no related complications and hazards.