How much pretransfusion testing should be done for a patient with anti-D, acquired by having received an injection of RhIG?

A colleague reports that when they identify anti-D in a patient at their institution, they inquire from the patient's physician about the patient recently receiving RhIG. If the patient has such a history within the previous few weeks, they report the antibody as probably due to RhIG administration. If the doctor orders RBC units crossmatched for the patient with detectable RhIG, they do an 'antiglobulin' crossmatch, rather than an immediate spin crossmatch. If the patient is scheduled for surgery and no units have been ordered, to be on the safe side, they treat these patient as if they have a potentially significant alloantibody, and per their local policy, they crossmatch two units of packed RBCs (with no charge to the patient) if only a type and antibody screen was ordered, in case the patient needs blood promptly. She asks if they are doing too much? She wonders what others are doing, specifically what is the practice of other institutions when a crossmatch is ordered for a patient with Anti-D possibly due to RhIG administration?

Editor's Note: Colleagues may find the discussion "Does a history of transient passively acquired anti-D from receipt of RhIG disqualify a patient for an electronic crossmatch?" to be germane to the above inquiry.

The following comments have been received.

ADDENDA Feb. 27, 2006

1. A colleague in Georgia reports that his transfusion service laboratory has observed that the vast majority of the patients who have had Rh Immune Globulin in the last trimester of pregnancy do not show the passive anti-D at or after the time of delivery in an antibody screening test, if they employ an indirect antiglobulin test using a tube method with a LISS (N-HANCE™) reagent. On the other hand, some of the passive anti-D antibodies are detectable at or after delivery when employing an indirect antiglobulin test using a GEL method. Consequently, to avoid detecting passive anti-D, if a patient has a history of a recent RHIG injection, they perform the antibody screening using the tube method (and not by the GEL method), and if the antibody screen by the tube method is negative, they report out the tube method results as negative; in the event that RBC transfusions are needed, they would issue the RBCs based on an immediate spin crossmatch. If, however, they do not elicit a clear history of administration of Rh Immune Globulin, they perform antibody screening using a GEL method. If the GEL test detects anti-D (even if it is later determined to be due to RHIG injection), they would use antiglobulin crossmatches in the event the RBCs were needed for transfusion.

ADDENDA Mar. 12, 2006

2. A medical technologist at a Regional Health Center in Texas reports that in their 350 bed hospital, if they can suspect (ascertain) that a patient's antibody screen is positive due to a recent injection of Rh immune globulin, they perform what they refer to as an "ANTI-D screen". One of their commercially available antibody identification panels has 3 or 4 vials containing Rh negative red cells that can be used to detect significant antibodies, except anti-D. If this ANTI-D screen is negative, they merely perform Immediate Spin crossmatches at the time an RBC transfusion is ordered, as if the antibody screen was negative. They report that the patient's plasma contains Anti-D probably due to Rh Immune Globulin, and the Anti-D screen as negative.

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