Effective Helper of Clinical Diagnosis: Immunodiagnosis

  • In vitro diagnosis (IVD) refers to the process of using in vitro detection reagents and instruments to detect blood, body fluids, tissues and other samples for the purpose of disease prevention, diagnosis, treatment detection, post-observation, health evaluation and genetic disease prediction. At present, in vitro diagnostics and laboratory medicine have formed an organic whole which is both different and closely related to each other. As the "tool" and "weapon" of laboratory medicine, in vitro diagnosis covers a wide range, and is applied in various aspects of disease prevention, diagnostic testing and post-treatment evaluation, and is a very important part of the medical and health industry.

    Meanwhile, immunodiagnosis, an important component of in vitro diagnosis, is used for the diagnosis of various diseases and the determination of immune status. In medicine, it is an important method to determine the cause of disease and lesion site, or to determine whether the immune status of the body is normal. In addition, it is also used in forensic blood stain identification, biochemical serum composition identification and research of species evolution. In addition, it has also been used in forensic medicine for the identification of blood stains, the identification of biochemical serum components and the study of species evolution, etc., which can be carried out in vivo and in vitro. Immunodiagnostic reagents are the most widely used in diagnostic kits and are widely used in hospitals, blood stations and physical examination centers. They are mainly used for hepatitis detection, venereal disease detection, tumor detection and pregnancy detection. Among them, immunodiagnosis includes radioimmunoassay, enzyme-linked immunoassay, chemiluminescence, etc. Enzyme-linked immunity: ELISA has the advantages of low cost and large-scale operation. Meanwhile chemiluminescence immunoassay: CLIA has the advantages of sensitive, rapid, stable, selective, reproducible, easy to operate, flexible and diverse methods.

    For pathogens that are medically difficult to detect, immunodiagnostic screening is often used. TORCH refers to can lead to congenital intrauterine infection and perinatal infection caused by perinatal malformation of pathogens, it is a set of English name abbreviations of pathogenic microorganisms, including T is the Toxoplasma, O are other pathogenic microorganisms, such as syphilis helicoid, Herpes zoster Virus, parvovirus B19, coxsackie Virus, etc., R is the Rubella Virus, H is Herpes simplex type I/II. TORCH infections have common characteristics, namely can cause maternal and infant infection. At present, the most convenient and commonly used early screening method in China is to use ELISA technology to detect specific IgM and IgG antibodies in human serum. Because IgM is an indicator of early infection and has a huge impact on the fetus, the detection of IgM has attracted much attention. The detection of specific IgM in the placenta is a reliable basis for the diagnosis of fetal intrauterine infection. The ELISA kit development makes it stable, high sensitivity, high specificity and low cost, so it is widely used in ordinary laboratories, but generally used for qualitative rather than quantitative analysis. At present, chemiluminescence method is usually used for quantitative detection. CLIA has high sensitivity, small variation within and between batches, and good anti-interference ability, which can remove the interference of virus IgG antibody and rheumatoid factors that may exist in the specimens, and is suitable for routine clinical work. Adenovirus is a kind of 70 ~ 90 nm diameter particles without envelope. It can infect the respiratory tract, gastrointestinal tract, urethra, bladder, eyes, liver, etc. About 1/3 of the known serotypes of human adenovirus are usually associated with human diseases. One serotype can cause different clinical disorders, and different serotypes can cause the same disorder. Adenovirus laboratory diagnosis is usually performed with serological methods. Double serum samples of patients in the acute phase and the convalescent phase are used for detection. If the serum antibody titer in the convalescent phase increases by 4 times or more than that in the acute phase, the diagnosis is significant. Rapid detection of serum can be performed by ELISA or latex agglutination test. We can also detect adenovirus infection in respiratory tract and gastrointestinal tract directly, which is faster and more sensitive. Immunofluorescence and enzyme immunoassay are commonly used methods. Compared with cell culture, the sensitivity of adenovirus measured by immunofluorescence is improved by 40%~60%.

    Immunological detection method is a series of experimental methods for the determination of antigens, antibodies and immune cells. With the interdisciplinary infiltration, the scope of immunology is expanding, and new immunological detection methods are emerging one after another. The application of immunological methods is also expanding, which not only becomes an important method for the diagnosis of a variety of clinical diseases, but also will continue to provide convenience for the research of many disciplines.