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Direct Coombs’ test

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

The direct Coombs’ test detects antibodies that are attached to the surface of red blood cells. It is used to diagnose conditions such as autoimmune hemolytic anemia.

5 Must Know Facts For Your Next Test

  1. The direct Coombs' test is also known as the direct antiglobulin test (DAT).
  2. It involves adding Coombs reagent, which contains anti-human globulin, to a patient's red blood cells.
  3. A positive result indicates that antibodies or complement proteins are bound to the surface of red blood cells.
  4. This test is crucial for diagnosing hemolytic diseases in newborns, such as hemolytic disease of the newborn (HDN).
  5. It can also be used to investigate transfusion reactions and autoimmune disorders.

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