Testing for Weak D Antigen: When is it Optional?

When is testing for weak D antigen optional (not required)?

A. Testing for weak D on potential transfusion recipient samples. B. Testing on donor red blood cells. C. Testing cord blood on infants born to Rh-negative moms D. Testing for Rh immune globulin workups.

Answer:

Testing for weak D antigen is optional (not required) when conducting transfusion recipient samples.

Testing for weak D antigen, also known as weak D phenotype, is optional (not required) when performing tests on potential transfusion recipient samples. Weak D occurs when red blood cells express less D antigen, making it challenging for conventional testing methods to detect the antigen, such as the spin tube method.

Despite the difficulties in detecting weak D antigen, it is possible to demonstrate this poorly expressed antigen by using anti-human globulin and a prolonged incubation period. The debate surrounding whether to regularly test for weak D antigen has persisted for years after its discovery.

In the context of pregnant women, the clinical implications of weak D antigen testing are a concern. The categorization of human blood types into two primary groups, based on the presence (Rh positive) or absence (Rh negative) of the Rh antigen, is crucial in understanding the need for testing weak D antigen in certain scenarios.