The Methods Module deals with some of the basic methods used in blood banking. Because many of the methods that are reviewed relate to detecting unexpected antibodies, this module assumes that the learner is familiar with the major blood group systems. Covered elsewhere are the specific methods associated with pretransfusion compatibility testing.
Not covered in this course are several antibody detection methods, including polyethylene glycol (PEG); solid phase adherance assays (SPAA); and methods that use microtitre plates and automated instruments. However, an overview is given in the Newer Methods section.
Transfusion medicine serology deals with the detection and identification of antibodies in patients requiring blood transfusion, in blood donors, in pregnant women, in infants suffering from HDN, and in patients with AIHA. With the exception of AIHA due to autoantibodies, there are several ways in which a person can be exposed to foreign blood antigens and produce antibodies.
These are usually IgG antibodies that result from a known exposure to red cells either via pregnancy or transfusion. Thus, immune antibodies are typically red cell stimulated.
These are usually IgM antibodies that result from an unknown antigenic stimulus such as bacteria, which have antigens on their surfaces that are chemically similar to blood group antigens, or food stuffs. Thus, naturally occurring antibodies are typically non-red cell stimulated. The term "naturally occurring" is a misnomer as these antibodies do have an antigenic stimulus, albeit an unknown one.
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