Answer:
Different monoclonal antibodies clone anti-D formulation used in Reagent manufacture.
Explanation:
The D antigen is a protein found on the surface of the red blood cell. It is also known as the Rh factor and it determines a persons blood type.
D negative means a person's blood does not contain the D antigen and D positive have the antigen.
Weak D phenotype is a weaken form of D positive where the D antigen per cell are fewer than the normal Rh positive cells.
Discrepancies such as the one in our question occur due to different monoclonal antibodies clone anti-D formulation used in Reagent manufacture.
Monoclonal antibodies clone anti-D formulations can vary in their ability to detect partial D antigen and weak D phenotype.
The two may have used different monoclonal antibodies clone anti-D formulation reagents.