Febrile/Cold Agglutinins

There is no special preparation.

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing where the needle was inserted.

This test is done to diagnose certain infections and find the cause of hemolytic anemia (a type of anemia that occurs when red blood cells are destroyed). Knowing whether there are warm or cold agglutinins can help explain why the hemolytic anemia is occurring and direct treatment.

Normal results are:

• Warm agglutinins: no agglutination in titers at or below 1:80
• Cold agglutinins: no agglutination in titers at or below 1:16

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

An abnormal (positive) result means there were agglutinins in your blood sample.

Warm agglutinins may occur with:

• Infections, including brucellosis, rickettsial disease, salmonella infection, and tularemia
• Inflammatory bowel disease
• Lymphoma
• Systemic lupus erythematosus
• Use of certain medicines, including methyldopa, penicillin, and quinidine

Cold agglutinins may occur with:

• Infections, such as mononucleous and mycoplasma pneumonia
• Chicken pox (varicella)
• Cytomegalovirus infection
• Cancer, including lymphoma and multiple myeloma
• Listeria monocytogenes
• Systemic lupus erythematosus
• Waldenstrom macroglobulinemia

Risks are slight but may include:

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

If a disease linked to cold agglutinin is suspected, the person needs to be kept warm.