In the UK, the recommended method for D typing of patients requires direct agglutination tests, in duplicate, with potent IgM monoclonal anti-D reagents. An antiglobulin test is not required. This means that very weak D red cells will be typed as D negative.
What is the importance of weak D testing?
The importance of weak D lies in the fact that it is much less antigenic as compared to Rh D and weak D red cells may be destroyed if transfused to a person having anti D. Hence, weak D donor units are currently labelled as Rh D positive. Weak D testing is not done for a recipient and they are labelled as Rh negative.
What is a weak D antigen?
Weak D antigen is a phenotype where the D antigen is weakly expressed on red blood cells, and this antigen cannot be detected by routine methods.
How do you test for weak D?
How do you test for weak D antigen?
To test for a weak expression of the D antigen. Red cells that react weakly or not at all in direct agglutination tests with anti-D may react with anti-D by the indirect antiglobulin test (IAT).
With current serologic testing, most individuals with weak D are typed as Rh-positive via direct agglutination testing using anti-D.
What is weak D blood type?
The weak D phenotype is a weakened form of D antigen that in routine D antigen testing will react with some anti-D but not with others (when 37 C incubation or an immediate spin is given). Weak D RBC has D antigen but fewer in number as compared to normal Rh D-positive red cells.
Who are routinely tested for weak D?
