Major Crossmatch Test

Cross Matching is a procedure performed prior to a blood transfusion to determine whether donor blood is compatible with recipient blood. Compatibility is determined through matching of different blood group systems, the most important of which are the ABO and Rh system, and/or by directly testing for the presence of antibodies against a sample of donor tissues or blood. The major cross match involves testing the patient’s serum with donor cells to determine whether the patient has an antibody which may cause a hemolytic transfusion reaction or decreased cell survival of donor cells. This is the most important cross-match.

Make sure the donor has been tested for the following diseases before the donation: ABO typing. Rh typing. Hepatitis B surface antigen. Hepatitis Core B antibody ( HBc-IgM ). Hepatitis C antibody. For Syphilis ( VDRL ) HIV SGPT ( ALT ). If possible do PCR for HCV and HIV. It is advisable that you should either wear a sleeve-less or a half-sleeve shirt or wearing a shirt with full- sleeves that can easily be rolled-up till elbow so that the doctor can take a blood sample easily.

The test is negative, or compatible, when the plasma is clear and the RBCs are readily suspended. A positive, or incompatible, test can have hemolysis or hemagglutination or both. All tests judged macroscopically to be negative for hemagglutination should be confirmed microscopically at low power.

Collect blood into an EDTA tube from recipient and possible donor(s)

An alcohol pad is used to clean the skin. A needle is then injected through the part of rinsed skin into to your vein or heel; specifically in the one that can be seen from the skin. The blood is dragged out from the needle by a nozzle. Centrifuge tube(s) at 1000 x 9 for 5 min. to separate plasma from red blood cells (RBCs). Remove plasma from each sample with a clean pipette and transfer to clean, labeled glass or plastic tubes. Wash RBCs 3 times with a normal saline solution; resuspend to make a 3-5% RBC suspension.