1. Does the patient have ITP as a diagnosis? If so, they probably received WinRho, which makes an Rh Pos person have a positive D alloantibody. 2. Another reason can be if the person has a "partial D." This is when the red cells are mising portions of D through inheritance, which in turn, makes the allo-D through high-incident D antigens that are missing on their red cells. How do you identify a partial D? If you work at a bigger hospital, they may have a "panel" of anti-D typing reagents...essentially this is a panel, just like a regular panel you would perform, but they are all different partial D's - in letters A through L. Panels like these are used for investiagional purposes only. We actually had a DIV (roman numeral D4) at our facility last week!! If you go to www.albabioscience.co.uk this shows you a bit more about this topic under products. Mer