MLT GlobeCrossmatch (compatibility test)
Blood Bank · also called Cross-match, Major crossmatch, Compatibility testing
What it measures
Checks that the patient's plasma does not react with the donor red cells chosen for transfusion. It is the final serological safety check before blood is issued.
Specimen and preparation
- Specimen: Patient plasma (EDTA) plus donor red cell segment
- Tube: Pink top
- Preparation: Use a correctly labeled sample collected within the valid window (often 72 h).
Reference range
| Group | Range |
|---|---|
| All | Compatible (no agglutination or hemolysis) |
Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.
Causes of high values
- Incompatible: ABO mismatch or labeling error
- Clinically significant alloantibody
- Autoantibody (all units incompatible)
- Rouleaux or cold agglutinins (false reaction)
Method
Immediate-spin or electronic crossmatch when screen is negative; full antiglobulin crossmatch when antibodies are present
Good to know
An ABO-incompatible crossmatch is a critical finding; stop and investigate identification errors immediately.
Related tests
📱 Practise with a timer, track your score and earn certificates in the free MLT Globe app – Google Play or practise online.