What does a negative blood type mean?
1 Answer
Dec 6, 2016
A negative blood type is one in which the D (or Rhesus) antigen is absent.
Explanation:
Apart from the four major blood groups, A, B, AB and O, there are sub-groups (sub-types) based on the presence or absence of the D (Rh) surface antigen.
If a person is genetically DD or Dd , the D surface antigen is expressed and the person is Rh positive.
If the person is genetically dd, the D surface antigen is not expressed and the person is Rh negative.