What is hepatitis A antibody test?
what is hepatitis A antibody detection?
hepatitis A antibody test is an examination method to clearly diagnose whether the subject is suffering from hepatitis A. The detection methods of hepatitis A antibody mainly include radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA).
hepatitis A is a liver disease caused by hepatitis A virus. The virus is transmitted by uninfected persons (or unvaccinated persons) ingesting food or water contaminated by the feces of hepatitis A virus infected persons. The disease is closely related to unsafe water, poor sanitation and poor personal hygiene habits. In terms of serotypes, there is only one hepatitis a serotype that can infect people, so there is only one antigen antibody system. IgM type antibodies are produced early after hepatitis A infection, which generally lasts for 8-12 weeks, a few can last for 6 months, and IgG type antibodies can exist for a long time. IgM is a marker of recent infection, and IgG is a marker of past infection.
hepatitis A antibody detection method
1 and radioimmunoassay (RIA)
radioimmunoassay is a labeled immunoassay with radionuclides as markers. It is used for quantitative determination of antigens in tested samples. It has high sensitivity and is often used for determination of trace substances. However, because this detection method can not detect substances that lose immune activity, and some substances with particularly low content in the body can not be determined. Therefore, enzyme-linked immunosorbent assay (ELISA) is often used to detect hepatitis A virus in clinic.
2. Enzyme linked immunosorbent assay (ELISA)
. It is the most widely used technology in enzyme immunoassay. The basic method is to adsorb the known antigen or antibody on the surface of the solid carrier, make the enzyme labeled antigen antibody react on the solid surface, and wash the free components in the liquid phase by washing method. The common ELISA methods include double antibody sandwich method and indirect method. The former is used to detect macromolecular antigens, and the latter is used to determine specific antibodies, such as anti LGM and IgG antibodies of hepatitis A virus.
hepatitis A antibody positive
hepatitis A antibody detection only if anti IgM antibody is positive, it can be diagnosed as hepatitis A infection. Positive detection of hepatitis A antibody indicates that there are two possibilities:
1, acute infection or recurrence.
anti IgM antibody is the earliest antibody after infection with hepatitis A virus, which appears about 1 week after onset. Its positive detection indicates recent infection, that is, the early stage of hepatitis A, which is a sign of acute infection. Anti IgG antibody is an indication of late infection, which is negative in the early stage of infection and positive in the later stage of acute and recovery.
2. There are antibodies after previous infection or vaccination.
anti IgG antibody is a protective antibody. If the anti IgM antibody is negative, the anti IgG antibody is positive, which indicates that it has been infected with hepatitis A in the past, but has been cured or vaccinated with hepatitis A vaccine, so it has immunity to hepatitis A.
hepatitis A antibody is negative
hepatitis A antibody is negative, indicating that neither hepatitis A virus nor hepatitis A vaccine has been inoculated, and there is no antibody against hepatitis A virus in the body. It is recommended to vaccinate hepatitis A vaccine in a regular hospital in time to actively prevent hepatitis A.
all kinds of studies show that hepatitis A is a sexually transmitted disease. Among the susceptible men who have negative hepatitis A antibody, the incidence rate of hepatitis A is 22%.
precautions for hepatitis A antibody detection
anti IgG antibody appears late and lasts for a long time. It is often negative in the initial stage of infection, which is often used for epidemiological investigation. If the antibody titer is low, it should be caused by rheumatic factor A. note that the antibody titer should be low every two weeks. The positive anti IgG antibody indicates that he has been infected with hepatitis A, but the titer of double anti IgG antibody increased by more than 4 times, which is also of diagnostic significance.