The primary purpose of the major cross-match, or compatibility test, is to prevent a possible transfusion reaction.

Major cross-match detects antibodies in the recipient’s serum that may damage or destroy the cells in the blood donor. The type and screen determine the ABO and RhD type as well as the presence or absence of unexpected antibodies from the recipient. The type and screen is a safe alternative for the routine type and cross-match ordered preoperatively for cases that may, but usually do not, require transfusion (e.g., hysterectomy, cholecystectomy). If blood is needed, a major cross-match must be done before transfusion.

• No cell clumping or hemolysis and absence of agglutination when serum and cells are appropriately mixed and incubated.

• The major cross-match shows compatibility between recipient serum and donor cells.

1. Obtain a 10-mL venous blood sample. Observe standard precautions.

2. Label the specimen with the following information:

   1. Patient’s full first and last names

   2. Patient’s healthcare record number

   3. Date and time of specimen collection

   4. Initials (if collected by laboratory personnel) or signature (if collected by nonlaboratory personnel) of phlebotomist

   5. Possibly a unique blood bank number (found on special blood bank identification band)

3. Attach a special blood bank band, at the recipient’s bedside, at the time of specimen collection. The blood bank band must remain attached to the patient’s wrist throughout the transfusion period. The same band may be used throughout one hospital admission as long as the information printed on the band is legible and the band is still securely attached to the patient’s wrist.

1. Cross-match incompatibility implies that the recipient cannot receive the incompatible unit of blood because antibodies are present.

2. A transfusion reaction occurs when incompatible blood is transfused, specifically if antibodies in the recipient’s serum cause rapid red blood cell destruction in the proposed donor.

   1. Certain antibodies, although not causing immediate red cell destruction and transfusion reaction, may nevertheless reduce the normal lifespan of transfused incompatible cells; this may necessitate subsequent transfusions.

   2. The patient will derive the most benefit from red cells that survive longest.

Pretest Patient Care

1. Explain purpose and procedure of cross-matching.

2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.