Coombs test

From WikiMD's Wellness Encyclopedia

Coombs Test also referred to as the Antiglobulin test, is a clinical laboratory assay that helps in identifying antibodies that can attach to the surface of red blood cells (RBCs) or platelets, leading to their destruction. This test plays a critical role in diagnosing certain blood disorders where the patient's immune system erroneously generates antibodies against their own RBCs or platelets. Moreover, it is utilized in the determination of blood type. The Coombs test is a two-part procedure, involving the Direct Coombs test and the Indirect Coombs test.

Direct Coombs Test[edit | edit source]

The Direct Coombs Test (Direct Antiglobulin Test, DAT) is employed to detect antibodies that are bound to the surface of red blood cells in the patient's body. A positive result typically indicates conditions such as autoimmune hemolytic anemia (AIHA), in which the body's immune system mistakenly produces antibodies against RBCs, causing hemolysis, or destruction of the red blood cells.[1]

Indirect Coombs Test[edit | edit source]

The Indirect Coombs Test (Indirect Antiglobulin Test, IAT) is used to screen a patient's serum for the presence of antibodies against RBCs. If these antibodies are present and are specific to antigens on the recipient's RBCs, they can cause transfusion reactions or Hemolytic Disease of the Newborn (HDN). It is thus an important part of pre-transfusion compatibility testing and prenatal testing of pregnant women.[1]

Clinical Significance[edit | edit source]

The Coombs test, both direct and indirect, plays a crucial role in the field of hematology and transfusion medicine. It helps in the diagnosis of autoimmune hemolytic anemia, monitors the condition of patients with chronic lymphocytic leukemia or lymphoma, assists in predicting and managing potential complications in blood transfusion, and provides vital insights into the hemolytic conditions of the newborn.

Methodology[edit | edit source]

The Coombs test involves the use of antiglobulin serum (Coombs reagent) that reacts with the antibodies on the red blood cells. The agglutination or clumping of RBCs indicates a positive test, demonstrating the presence of surface antibodies on the red blood cells.[1]

Coombs test Resources
Coombs test Resources
  1. 1.0 1.1 1.2 "Coombs Test". 2020. Retrieved 2023-05-18.

Contributors: Prab R. Tumpati, MD