From a transfusion medicine physician's point of view, this case illustrates one of the most troublesome situations encountered: How does one safely transfuse a patient when compatible blood is unavailable? A panreactive antibody present in a patient's plasma, whether caused by an autoantibody or a drug-induced antibody, may interfere with routine blood bank testing used to detect alloantibodies. The panagglutinating antibody may mask a coexisting alloantibody and place the patient at increased risk for a hemolytic transfusion reaction. Additional testing to determine the presence of underlying alloantibodies may take several hours to perform and may delay finding appropriate blood for the patient. Two critical pieces of information necessary for determining the risk/benefit of transfusion of incompatible blood are the urgency of the present clinical situation and the pregnancy and transfusion history of the patient. Men without a transfusion history are at negligible risk of having alloantibodies, and incompatible blood may safely be given. Patients with previous pregnancies or transfusions are at greater risk of having underlying alloantibodies, and the consideration of the clinical need and benefits of transfusion must be weighed more carefully. This patient's history of a previously identified anti-E antibody suggests she had previously been pregnant or undergone transfusion, which increases the likelihood that other unidentified alloantibodies may be present. Although this finding puts her at increased risk for a hemolytic transfusion reaction, the rapid decline in her hematocrit to 11.8% warrants the emergent release of blood before completing the usual pretransfusion testing. The risk of a hemolytic transfusion should not deter the clinician from transfusing a patient when withholding the transfusion would place the patient in a life-threatening situation. Transfusion should never be withheld solely on the basis of incompatible serology test results.
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Authors' Disclosures or Potential Conflicts of Interest: No authors declared any potential conflicts of interest.
- Received for publication September 9, 2011.
- Accepted for publication September 13, 2011.
- © 2012 The American Association for Clinical Chemistry