Grupos sanguíneos
Grupos sanguíneos: ABO
The blood groups refer to the presence on human red blood cells of certain antigens, the blood group factors. One very important group of factors present on the red blood cells is the ABO system. The ABO group of a person depends on whether his/her red blood cells contain one, both, or neither of the 2 blood group antigens A and B. There are, therefore, 4 main ABO groups: A, B, AB and O. Antibodies (agglutinins) for the antigens A and B exist in the plasma and these are termed anti-A and anti-B. The corresponding antigen and antibody are never found in the same individual since, when mixed, they form antigen-antibody complexes, effectively agglutinating the blood.
Testing for ABO Group - Procedure
One end of a slide is labelled Anti-A, and the other Anti-B. A drop of Anti-A test serum is added to the end marked Anti-A, and a drop of Anti-B serum is added to the end marked Anti-B.
One drop of blood is added to each end of the slide, and mixed well, using separate wooden sticks.
The results are read directly from the slide. The subject is blood group A if agglutination occurred with the Anti-A test serum; group B if agglutination occurred with the Anti-B test serum; group AB if agglutination occurred with both test serums, and O if there was no agllutination in either case. In the sample to the right, we conclude the subject has type A blood.
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