In Medinfo HIIG, one sets parameters to determine which antigens must be matched to allow a RBC product to be released. These criteria may include:
Number of and timing of ABO/D typings
Permissible ABO/D substitutions
Required antigen matches
Optional antigen matches
Exact wording of conditional and blocked combinations
For ABO/D typing, a minimum of two typings must be on record for routine release and the last typing done within 72 hours. If not, emergency release must be selected. ABO-incompatible selections must be blocked. For D-negative patients, only D-typed units may be selected. D-incompatible transfusions will trigger a message to use D-compatible for females <50 years.
Required antigen typings include using antigen-negative for patients having antibodies against the specified antigen, e.g. D-negative RBCs for patients with active anti-D, c-negative for patients with anti-c, K-negative for anti-K, etc.
Certain antibodies will trigger a message to flag the use of unmatched units but not block the release.
The attached document shows sample settings for RBC release. Note that these rules are user-definable.