Type & Cross-match

Transfusion Medicine

Blood Typing	Defining red cell blood group antigens by reaction with reagent antibodies in an agglutinating or hemolytic assay.
Minor Crossmatch	React recipient red cells with donor serum or plasma to detect antibodies that could destroy recipient red cells. Not of concern with packed cell transfusions.
Major Crossmatch	React donor red cells with recipient serum or plasma to detect antibodies that would destroy transfused cells. Should be done in addition to typing in a previously transfused patient.

Reasons for Blood typing and Crossmatching:

Prevent formation of isoantibodies which may cause a delayed transfusion reaction and subsequent hemolytic anemia.

Avoid sensitization of future breeding stock and subsequent hemolytic disease of newborns through receiving colostral antibodies.

Limitations of Crossmatching:

Hemolyzing antibody may not be detected in a crossmatch looking for agglutination.

Agglutinizing reaction: Notice the clumps of red blood cells aggregating on the bottom of the tube on the right hand side.

Hemolyzing reaction: Notice the bright pink color of the reagent in the tubes after mixing. This indicates lysis of red blood cells.

For more information . . .

Veterinary Laboratory Medicine, Duncan, Prasse, and Mahaffey page 19-20.
Veterinary Laboratory Medicine, Interpretation & Diagnosis. Meyer & Harvey, pages 142-143.