Transfusion
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Monoclonal antibodies (MoAbs) are increasingly integrated in the standard of care. The notion that therapeutic MoAbs can interfere with clinical laboratory tests is an emerging concern that requires immediate recognition and the development of appropriate solutions. Here, we describe that treatment of multiple myeloma patients with daratumumab, a novel anti-CD38 MoAb, resulted in false-positive indirect antiglobulin tests (IATs) for all patients for 2 to 6 months after infusion. This precluded the correct identification of irregular blood group antibodies for patients requiring blood transfusion. ⋯ CD38 MoAb therapy causes false-positive results in the IAT. The reliability of the test could be restored by adding a neutralizing agent against the CD38 MoAb to the patient's plasma. This study emphasizes that during drug development, targeted therapeutics should be investigated for potential interference with laboratory tests. Clinical laboratories should be informed when patients receive MoAb treatments and matched laboratory tests to prevent interference should be employed.