Fluorescence in situ hybridization – FISH test

In Russia, there is a risk of disappearance of tests for genetic breakdowns and oncological diseases. According to information from some laboratories, there is a risk of stopping the so-called FISH studies. It can happen because the American manufacturer of equipment, reagents, consumables, and software Thermo Fisher Scientific left the country.

Fluorescence in situ hybridization (FISH) is a molecular cytogenetics technique that identifies a specific chromosome or part of a cell’s chromosome. The FISH method can detect small changes in chromosomes that cannot be detected by conventional cytogenetic methods.

Very roughly, the principle of the FISH test can be described as follows: there is a set of DNA samples of different composition. These samples are labeled with a fluorescent label. If DNA fragments compatible with the sample are present in the patient’s material, they bind, and the researcher can detect this binding using a fluorescent microscope, in which a fluorescent signal appears (a positive FISH test result). The method makes it possible to evaluate not only the presence of a fluorescent signal, but also its intensity and localization. Thus, the FISH test is not only a qualitative, but also a quantitative method.

Among the advantages of the method the possibility of using various biomaterials for research, high sensitivity, and accuracy in determining chromosomal abnormalities in tissues with low proliferative activity can be noted.

FISH tests are not so popular among genetic tests in Russia (their proportion is no more than 5 %), but recently the frequency of their use has increased. Basically, the scope of their application is the differential diagnosis of malignant diseases, primarily in the field of oncohematology.

In addition, FISH tests are also used to diagnose genetic disorders, such as infertility due to hereditary causes, as well as in prenatal diagnosis.

Currently, there are certain problems with FISH test consumables, however, leaving only Thermo Fisher Scientific will not completely block the use of this method, since many companies produce FISH test reagents, for example, Kreatech, Abbot, CytoTest.


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