Skip to content

Direct Coombs Test

Published: July 27, 2026Updated: August 25, 2026

The Direct Coombs Test measures antibodies attached to the surface of red blood cells, helping to diagnose autoimmune hemolytic anemia and hemolytic disease of the newborn.

Quick summary

The Direct Coombs Test detects antibodies on the surface of red blood cells.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
result
Clinical utility
diagnostic
Result kind
qualitative
FDA-cleared
Bio-Rad Coombs Direct, Ortho Clinical Diagnostics Coombs
interpretation: {"text":"Indicates the presence of antibodies or complement proteins on the surface of red blood cells, suggesting autoimmune hemolytic anemia or hemolytic disease of the newborn.","label":"Positive"}; {"text":"Suggests the absence of antibodies or complement proteins on the surface of red blood cells, making certain conditions less likely.","label":"Negative"}

The Direct Coombs Test, also known as the direct antiglobulin test (DAT), is used to detect antibodies or complement proteins bound to the surface of red blood cells.

This test is crucial in diagnosing autoimmune hemolytic anemia, where the body's immune system attacks its own red blood cells.

It is also used to diagnose hemolytic disease of the newborn, which occurs when maternal antibodies attack the baby's red blood cells.

Frequently asked questions

What does a positive Direct Coombs Test mean?
A positive result indicates that antibodies or complement proteins are attached to the red blood cells, which can be a sign of autoimmune hemolytic anemia or hemolytic disease of the newborn.
Can medications affect the Direct Coombs Test result?
Yes, certain medications can cause a positive result by inducing the formation of antibodies against red blood cells.
  1. 1
    American Society of HematologySource
  2. 2
    Mayo ClinicSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy