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19001717 The "identification of abnormal antibodies (test tube technique)" refers to a laboratory method, usually called an "indirect antiglobulin test (IAT)", where a patient's blood serum is mixed with red blood cells of known antigen profiles in test tubes to identify the presence of specific, potentially harmful antibodies by observing visible agglutination (clumping) under a microscope; this is commonly used in blood transfusion testing to detect unexpected antibodies in a patient's blood before a transfusion.
