What is the difference between the Direct Coombs (Direct Antiglobulin) test and the Indirect Coombs (Indirect Antiglobulin) test?

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Last updated: February 8, 2025 • View editorial policy

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.

Clinical Applications

  • The Direct Coombs test is a critical step in the evaluation of hemolysis and helps to distinguish between immune and non-immune causes of hemolysis 2, 4.
  • The Indirect Coombs test is an important tool in transfusion medicine and helps to prevent transfusion-related complications 1.

References

Research

Role of gel based technique for Coomb's test.

Indian journal of pathology & microbiology, 2006

Research

The Direct Antiglobulin Test: Indications, Interpretation, and Pitfalls.

Archives of pathology & laboratory medicine, 2017

Research

[Haemolysis: role of the direct antiglobulin test and eluate].

Nederlands tijdschrift voor geneeskunde, 2018

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.