African American women transfused with two week ago with 2 units RBC, hemoglobin dropping and is sympatric. Patient has a positive screen now, anti-D like identified. Patient is group O, Rh positive. Is there a rare antibody that we did not identified?

Well, there always could be, but it is much more likely that she has a Partial D type, such as Partial D Type III, and she has made an anti-D.  Partial D Type IIIa, IIIb and III Type V are all found in African American population, but, unless you perform molecular techniques, you would not be able to tell, as ALL monoclonal anti-D reagents so far produced react well with these types and, indeed, although they are partial D types, they actually have exulted expression of the D antigen, so you could not even detect them from weakened expression.

However, beware, if her Hb drops to a level below that of her pre-transfusion level, it could be a case of hyperhaemolysis, accompanying a delayed haemolytic transfusion reaction.  As she is symptomatic, it sounds like she needs a further transfusion, but this is not without danger.  Firstly, the blood should be D Negative, but the clinician may also consider it wise to cover the transfusion with high-dose IVIgG (about 1g/kg body weight) and IV methylprednisolone.

Thank you very much Malcolm. Very detailed explanation. I am waiting on the molecular testing results now and yes she has been transfused and we are issuing Rh negative of course.