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Indirect antiglobulin test (IAT)

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

Definition

The indirect antiglobulin test (IAT) is a laboratory technique used to detect antibodies in a patient's serum that are capable of binding to red blood cells. It is commonly used in blood compatibility testing and antibody screening.

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5 Must Know Facts For Your Next Test

  1. IAT involves incubating the patient's serum with reagent red blood cells, followed by adding antihuman globulin.
  2. A positive IAT indicates the presence of antibodies against red blood cell antigens in the patient's serum.
  3. The test is pivotal for pre-transfusion testing and for pregnant women to check for antibodies that might affect the fetus.
  4. IAT is different from the direct antiglobulin test (DAT), which detects antibodies directly bound to red blood cells in vivo.
  5. Common uses of IAT include compatibility testing before blood transfusion and detection of atypical antibodies.

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