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Hospital diagnosis of ToRCH infection method(二)

Dec 22, 2017

Immunological diagnosis ---- Determination of serum antibodies

(1) Fluorescence immunoassay (FIA) and radioimmunoassay (RIA)

FIA requires expensive fluorescence microscopy, stained specimens can not be long-term preservation, should not be accurate quantitative, but also determine the results with a certain subjectivity. Although RIA has good sensitivity, specificity and reproducibility, isotopes are expensive and have short half-lives and require complex instrumental recordings. In addition, isotopes require specialized safety equipment for transport, storage, application and disposal, so the use of RIA has been severely limited.

(2) ELISA 

In recent years, more reports have mainly serological diagnostic techniques, the technology started in the late 19th century, mainly to detect serum antibodies. This is a quick and easy inspection technique and is widely used in many diseases. In 1976, Nussau first applied enzyme-linked immunosorbent assay (ELISA) to immunological diagnosis. Because ELISA has the similar sensitivity with isotope detection and avoids the radioactive contamination of isotope, ELISA is highly evaluated internationally and is regarded as a revolutionary achievement in modern serology. ELISA technology in the application of virology in 1974 in the United Kingdom was successful, then there has been no discontinuation of this research at home and abroad. ELISA is currently the most commonly performed method in hospitals to detect "ToRCH" infection, which is specific for the determination of specific antibodies against "ToRCH" pathogens such as IgG and IgM in serum. The introduction of this method has facilitated the development of ToRCH immunological diagnosis. In general, if IgM is positive, it means that pregnant women may have "ToRCH" infection (or primary infection) in the near future, which may cause fetal malformations. If IgG is positive, it often means that there was a "ToRCH" infection in the past, Little effect, in China's women of childbearing age, about 90% of the population rubella and cytomegalovirus IgG positive.

Antibody ELISA, the main problem is the antigenicity is weak, resulting in the ELISA technology is difficult to make substantial progress, and can not be single-serving operation, only the bulk test. In addition, the original reagents expensive abroad, the domestic reagent negative background, poor specificity, false positives or false negatives prevail, the quality is not satisfactory.

(3) gold standard kit

Simple operation, suitable for grass-roots units to use, most of the specificity is not strong, the sensitivity is not high, but also to determine the results with a certain subjectivity.