What is the purpose of the Coombs test?

The Coombs test is a specific laboratory test that allows you to identify antibodies that are in the blood plasma or on the surface of the erythrocyte. This procedure allows to diagnose immune hemolytic anemia, including in newborns, and also to reveal hemolytic transfusion reactions. The Coombs test is actively used in forensic science and scientific genetics in order to determine erythrocyte antigens. Observance of all the rules of implementation of such an analysis allows to obtain the most reliable result.

The purpose of the antiglobulin test

The Coombs direct test allows detection of anti-erythrocytic antibodies, which are fixed on erythrocytes. A positive reaction in such a study indicates the development of autoimmune hemolytic anemia. It should be noted that a negative result does not exclude the presence of autoimmune disease, since antibodies are often in a free form, that is, they do not have a connection with erythrocytes. In such cases, it is advisable to conduct an indirect Coombs test, which will determine the autonomous substances in the blood serum.

How is the analysis done?

З The venous blood sample is performed in the morning on an empty stomach, despite the fact that no significant factors influencing the final result of such a test were found. Store the material taken at a temperature of 2 to 8 ° C for no longer than seven days. In order for the indicators of this study to be as accurate as possible, whole blood for the first two hours must be delivered to the laboratory. Ideally, the Coombs test should show a negative result, which indicates the absence of hemolytic changes in the body.

Decoding of totals

The Coombs test is a rather laborious method of research, which requires careful and accurate implementation. When using this test, there may be some difficulties associated with incorrect interpretation of the final results due to a weak manifestation of positive reactions. It should be noted that the unreliability of the analysis - namely, the positive test of Coombs - may result from ineffective washing of red blood cells, contact with oily
Surface, and also neutralization of antiglobulin reagents by components Serum. Another drawback of this method of investigation is the instability of the material, the storage of which has certain features.

The cause of a false negative result can be excessive shaking of the red blood cell suspension during resuspension. Erroneous results may also be due to the presence of anti- complementary antibody impurities that are adsorbed upon incubation on the surface of the tested red blood cells, resulting in the appearance of a positive result. If the test samples are thoroughly washed and the reaction conditions are controlled, these drawbacks can be easily eliminated, which will increase the chances of obtaining the most reliable Coombs test.