The Positive Direct Antiglobulin Test - Where Do We Go from Here?

The direct antiglobulin test (DAT) is an in vitro evaluation performed to determine if in vivo sensitization of RBCs has occurred. Since its discovery in 1945 by Coombs, Mourant, and Race, the DAT, when combined with accurate clinical information, remains one of the most effective tests in the blood bank.

Although controversy exists regarding when and how often this test should be performed, the teleconference will focus on patient clinical history and what additional testing may be appropriate based on the available information (including autocontrol testing). Correct interpretation of the DAT, autocontrol, and eluate testing allows for expedited transfusion recommendations from the blood bank laboratory.

The investigation of a positive DAT due to passively acquired means will focus on:

• Post-transfusion alloantibody coating donor RBCs.
• Alloantibody acquired through intravenous IG and RhIG injections.
• Hemolytic disease of the fetus and newborn (HDFN).

Clinical causes of a positive DAT, such as drug-induced hemolytic anemia and warm autoimmune hemolytic anemia, in addition to causes of misleading DAT results, will also be explored.

Intended Audience: Pathologists, Residents, Laboratory Managers, Bench Supervisors, Bench Technologists & Technicians, Students

The ASCP designates this educational activity for a maximum of 1 AMA PRA Category 1 Credits™. Physicians should only claim credit commensurate with the extent of their participation n the activities.

ASCP designates this activity for a maximum of 1 CMLE credits. This activity meets CMP and state licensure requirements for laboratory personnel.