Cold Agglutinins

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Test Overview

A cold agglutinins blood test is done to check for conditions that cause the body to make certain types of antibodies called cold agglutinins. Cold agglutinins are normally made by the immune system in response to infection. They cause red blood cells to clump together (agglutinate) at low temperatures. See a picture of the immune system .

Healthy people generally have low levels of cold agglutinins in their blood. But lymphoma or some infections, such as mycoplasma pneumonia, can cause the level of cold agglutinins to rise.

Higher-than-normal levels of cold agglutinins generally do not cause serious problems. Sometimes high levels of cold agglutinins can cause blood to clump in blood vessels under the skin when the skin is exposed to the cold. This causes pale skin and numbness in the hands and feet. The symptoms go away when the skin warms up. In some cases, the clumped blood cells can stop the flow of blood to the tips of the fingers, toes, ears, or nose. This is like frostbite and can cause tissue damage. In rare cases, it can cause gangrene.

Sometimes high levels of cold agglutinins can destroy red blood cells throughout the body. This condition is called autoimmune hemolytic anemia.

Last updated:	June 12, 2008
Author:	Maria G. Essig, MS, ELS
Reviewed By:	Anne C. Poinier, MD - Internal Medicine, W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
Editors:	Susan Van Houten, RN, BSN, MBA, Tracy Landauer