Question 14

How is blood typed and cross-matched?

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College Answer

An opening statement of the importance of compatibility testing helped explain the relevance 
of the process. A brief description/table of agglutinogens (membrane antigens) along with 
Agglutinins (IgM Antibodies) was helpful.
Typing is the testing of individual red blood cells (donor and recipient) with anti-sera 
containing anti-A, B and AB antibodies. A positive test results in agglutination. Red cells with 
known antigens (A, B and O) are then tested with sera (reverse grouping). When discussion 
antibody screening, a mention of Rhesus antibodies along with testing for minor antibodies 
(Kell, Duff etc.) was expected.
Cross matching consists of the saline agglutination test andiIndirect Coombs testing. (This 
involves incubation, washing and testing with antiglobulin serum).
Many answers confused the processes of typing, antibody screening and cross matching.