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

Area of Science:

• Laboratory Medicine
• Immunology
• Hematology

Background:

• The direct antiglobulin test (DAT), also known as the Coombs test, is a cornerstone of laboratory medicine.
• Despite its simple design, the DAT presents complexities in application and interpretation, often leading to inaccurate results.

Purpose of the Study:

• To provide practicing pathologists with a comprehensive guide to the DAT.
• To clarify appropriate clinical situations for DAT use and highlight disease-specific limitations.
• To identify and explain common pitfalls, including causes of false-positive and false-negative results.

Main Methods:

• Review of the historical development of the DAT.
• Explanation of the clinical laboratory procedures for performing the DAT.
• Analysis of clinical scenarios where the DAT is indicated.
• Discussion of DAT interpretation guidelines.
• Identification of factors contributing to DAT assay inaccuracies.

Main Results:

• The DAT is a widely utilized but complex diagnostic tool.
• Understanding specific clinical contexts and potential pitfalls is crucial for accurate DAT interpretation.
• False-positive and false-negative results can significantly impact patient diagnosis and management.

Conclusions:

• The DAT remains a valuable assay when used judiciously.
• Pathologists require clear guidance on DAT application, interpretation, and limitations to optimize its diagnostic utility.
• Awareness of potential pitfalls is essential for minimizing errors in DAT testing.