Test Overview
A cold agglutinins blood test is done to check for conditions that
cause the body to make cold agglutinins, or
antibodies. 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 an illustration
of the immune system
.
Healthy people generally have low levels of cold agglutinins in
their blood. However, some infections, such as pneumonia caused by mycoplasma or
lymphoma 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.