Coombs Test (Direct and Indirect)

The Coombs Test at Pamel Laboratories includes both Direct (DAT) and Indirect (IAT) testing methods, used to detect antibodies that affect red blood cells. These tests play a crucial role in diagnosing and managing autoimmune hemolytic anemia, hemolytic disease of the newborn (HDN), and ensuring safe blood transfusions and pregnancy care.

1. Direct Coombs Test (Direct Antiglobulin Test – DAT):

This test detects antibodies or complement proteins attached directly to the surface of red blood cells. It is primarily used to diagnose conditions where the body is attacking its own red blood cells, such as:

• Autoimmune hemolytic anemia

• Hemolytic transfusion reactions

• Hemolytic disease of the newborn (HDN)

2. Indirect Coombs Test (Indirect Antiglobulin Test – IAT):

This test screens for free-floating antibodies in the bloodstream that could attack transfused red blood cells or cross the placenta during pregnancy. It is essential for:

• Pre-transfusion compatibility testing

• Prenatal antibody screening in Rh-negative pregnant women

• Assessing risk of Rh incompatibility and HDN

Purpose of the Test:

• Diagnose immune-mediated hemolytic anemia

• Screen pregnant women for Rh and other red cell antibodies

• Ensure blood transfusion compatibility

• Investigate causes of unexplained anemia or jaundice

Sample Type: Venous blood

Turnaround Time: 24–48 hours

Test Method: Antiglobulin testing using gel card or tube method

Result Interpretation:

• Positive DAT: Antibodies are bound to red blood cells (suggests autoimmune or transfusion-related hemolysis)

• Positive IAT: Antibodies are present in plasma (potential incompatibility risk)

• Negative: No antibodies detected