TORCH IgM
The device code TORCHM.CE is intended to be used for the first screening of women in pregnancy, and in other “risk patients” in order to point out those samples that are positive for IgM to any of the TORCH infectious agents. In case the assay turns out to be positive, the clinician then on such patient will go throughout specific TORCH tests able to determine which TORCH pathogen is involved in the infection.
TORCH microorganisms are ubiquitous human pathogens, whose infections continue to be an important health problem in certain patient populations, such as pregnant women, newborns, graft recipients of solid organs or bone marrow, and AIDS patients. In these last groups, Toxoplasma and CMV are a major cause of morbidity and mortality. The screening of TORCH specific IgM antibodies, even if does not indicate which microorganism is involved, is of great value in the first diagnosis of acute/primary infections or reactivation of a latent one, particularly in the absence of typical clinical symptoms, as usually happens for CMV and for Toxoplasma.
Recently developed IgM capture ELISA’s for TORCH, taking advantage of specific synthetic antigens or highly purified native ones, provide the clinician with an highly specific and reliable diagnostic test, not affected by Rheumatoid Factor, for the monitoring of such “risk” populations.
The assay is based on the principle of “IgM capture” where IgM class antibodies in the sample are first captured by the solid phase coated with goat anti hIgM antibody. After washing out all the other components of the sample and in particular IgG antibodies, in the 2nd incubation bound anti TORCH IgM are detected by the addition of a complex composed of TORCH antigens and TORCH conjugate labeled with peroxidase (HRP). After incubation, microwells are washed to remove unbound conjugate and then the chromogen/substrate is added.
In the presence of bound conjugate the colorless substrate is hydrolyzed to a colored end-product, whose optical density may be detected and is proportional to the amount of IgM antibodies to one or more TORCH antigen/s in the sample.
A Confirmation Test is described how to control whether the positivity shown by a sample is true or not (Confirmation Test), helpful for the clinician to make a correct interpretation of results.
It is required to test positive sample in specific: Toxoplasma IgM, Rubella IgM, HSV IgM, CMV IgM in order to know what infection is currently present.
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