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Hospital diagnosis of ToRCH infection method(三)

Dec 22, 2017

Molecular biology diagnostic techniques

Since the 1990s, with the rapid development of molecular biology in the field of medicine, researchers have introduced the principles of molecular biology into the ToRCH experimental research. Polymerase chain reaction (PCR) is a molecular biologic diagnostic technique based on nucleic acid biochemistry. It is one of the most valuable research methods in the field of biomedicine. Since the introduction of ToRCH in 1989, it has become the focus of much attention in the field of bacteriological diagnosis. After years of hard work accumulated a wealth of information and experience, so that this method continues to improve, and its responsive, specific and fast in a large number of data reports be affirmed. The technical operation of PCR is not complicated, but requires very high technical quality. False positives due to aerosol pollution amplification and false negatives due to the presence of inhibitory substances in samples, as well as the lack of standardization and standardization, are the keys to the credibility of PCR results. PCR is highly sensitive and can detect pathogens directly, but can not determine antibody levels in the population, and requires high levels of lab and reagent. In operation, the frequency and concentration of the cycle more affect the test results, increasing non-specific problems produce false positives. There are many reasons for the occurrence of false-negative results, mainly due to a variety of reasons, such as reduced enzyme activity, too little template and primer effects are affected and other factors.

Significance of detection of IgG and IgM antibodies: The body has a certain immunity, when the body suffers from pathogen infection, the body will produce the corresponding antibodies (immunoglobulin, Ig) to resist pathogens to protect the normal functioning of the body. The general rule is to first produce IgM antibodies (IgM antibodies appear earlier (disease period of 7 to 8 days), quickly rose to a certain titer, then rapidly dropped to lower levels in the body can be maintained for several weeks to several months , And occasionally more than one year.And then produce IgG antibodies, IgM antibody titer quickly began to decline to a low level after reaching a peak, is generally not easy to detect after the drop, and IgG antibodies peaked after the basic stability in a more High titers and continued for a long time.Check out the specific IgM antibody shows that patients with recent infections, latent virus is activated when the recurrence of infection can also detect IgM antibodies.Is detected IgG antibodies have been infected, and there is a certain Immune level.When patients with secondary infection, IgM and IgG can rise rapidly to higher titers, including IgG increased significantly (generally can rise more than 4 times the level), so if clinically detected high drop Degree of IgG, it means that the infection again.