The Coombs test is an immunohematology assay used in blood transfusion medicine and autoimmune hemolytic anemia diagnosis.

Direct Coombs Test (DCT):

Detects antibodies or complement proteins bound to the surface of RBCs.

Used in diagnosing autoimmune hemolytic anemia, hemolytic disease of the newborn, and transfusion reactions.

Indirect Coombs Test (ICT):

Detects antibodies present in the patient’s serum that can bind to RBC antigens.

Used in cross‑matching blood before transfusion and in prenatal testing for Rh incompatibility.

Both tests are critical for safe blood transfusion practices and for identifying immune‑mediated hemolysis.

ormal Result: Negative (no antibodies detected).

Abnormal Findings:

Positive DCT: Indicates autoimmune hemolytic anemia, transfusion reaction, or hemolytic disease of the newborn.

Positive ICT: Indicates presence of alloantibodies in serum, risk of transfusion reaction, or maternal antibodies against fetal RBCs.

Clinical Use:

Ensures compatibility in blood transfusions.

Detects immune‑mediated destruction of RBCs.

Supports diagnosis of hemolytic anemias and Rh incompatibility.