From the Research
Difference between Direct and Indirect Coombs Test
The Direct Coombs test, also known as the Direct Antiglobulin Test (DAT), and the Indirect Coombs test, also known as the Indirect Antiglobulin Test (IAT), are two different laboratory tests used to detect immune-mediated disorders 1.
Key Differences
- The Direct Coombs test detects immunoglobulin and/or complement on the surface of red blood cells, which helps to identify immune causes of hemolysis 2.
- The Indirect Coombs test detects the presence of antibodies against red blood cells in the serum, which helps to identify potential transfusion-related complications 1.
- The Direct Coombs test is used to diagnose autoimmune hemolytic anemia, transfusion-related hemolysis, and hemolytic disease of the fetus/newborn, among other conditions 2.
- The Indirect Coombs test is used to screen for antibodies against red blood cells before transfusion and to investigate transfusion-related reactions 1.
Test Methods and Interpretation
- Both tests can be performed using different methods, including tube tests, gel technology, and microcolumn assays 1, 3.
- The interpretation of the test results requires careful consideration of clinical and laboratory data to avoid false-positive or false-negative results 3, 2.
- The eluate test can be used in conjunction with the Direct Coombs test to determine the specificity of autoantibodies and increase the specificity of the test 4.