Coombs Test, Indirect Antiglobulin Test (IAT)

The Indirect Coombs Test (also known as the Indirect Antiglobulin Test) is a blood test used to detect antibodies in a person’s blood that may attack and destroy their red blood cells. It is primarily used in the context of blood transfusions, pregnancy, and autoimmune hemolytic anemia. In this test, blood serum is incubated with red blood cells from a donor or known source. If the patient has antibodies that bind to the red cells, they will cause agglutination (clumping).

Why consider this test?

• Blood transfusion compatibility: To ensure the patient’s blood does not react with transfused blood. It is done prior to blood transfusions to avoid hemolytic reactions.
• Pregnancy-related testing: Used in cases where a pregnant person may be at risk for Rh incompatibility with their fetus, which can lead to hemolytic disease of the newborn (HDN).
• Detecting autoimmune hemolytic anemia: This test helps diagnose conditions where the immune system mistakenly attacks red blood cells.

Who should get this test done?

• Pregnant individuals at risk for Rh incompatibility or HDN.
• Patients requiring a blood transfusion, to ensure compatibility.
• Individuals with autoimmune hemolytic anemia or unexplained hemolysis.

More Information

The Indirect Coombs Test is important in blood banking, ensuring the safety of blood transfusions. It helps identify any unexpected antibodies that could cause transfusion reactions.