Febrile/cold agglutinins
Cold agglutinins; Weil-Felix reaction; Widal test; Warm agglutinins; AgglutininsAgglutinins are antibodies that cause the red blood cells to clump together.
Antibodies
An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples of antigens include micr...
- Cold agglutinins are active at cold temperatures.
- Febrile (warm) agglutinins are active at normal body temperatures.
This article describes the blood test that is used to measure the level of these antibodies in the blood.
How the Test is Performed
Blood sample is needed
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
How to Prepare for the Test
There is no special preparation.
How the Test will Feel
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.
Why the Test is Performed
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.
Hemolytic anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Normally, red ...
Normal Results
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.
What Abnormal Results Mean
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
Brucellosis
Brucellosis is a bacterial infection that occurs from contact with animals carrying brucella bacteria.
ImageRead Article Now Book Mark ArticleSalmonella infection
Salmonella enterocolitis is a bacterial infection in the lining of the small intestine that is caused by Salmonella bacteria. It is a type of food p...
ImageRead Article Now Book Mark ArticleTularemia
Tularemia is a bacterial infection in wild rodents. The bacteria are passed to humans through contact with tissue from the infected animal. The bac...
ImageRead Article Now Book Mark Article - Inflammatory bowel disease
- Lymphoma
- Systemic lupus erythematosus
- Use of certain medicines, including methyldopa, penicillin, and quinidine
Cold agglutinins may occur with:
- Infections, such as infectious mononucleosis and mycoplasma pneumonia
- Chicken pox (varicella)
- Cytomegalovirus infection
- Cancer, including lymphoma and multiple myeloma
Multiple myeloma
Multiple myeloma is a blood cancer that starts in the plasma cells in the bone marrow. Bone marrow is the soft, spongy tissue found inside most bone...
ImageRead Article Now Book Mark Article - Listeria monocytogenes
- Systemic lupus erythematosus
- Waldenström macroglobulinemia
Risks
Risks are slight but may include:
- Excessive bleeding
-
Fainting or feeling lightheaded
Fainting
Fainting is a brief loss of consciousness due to a drop in blood flow to the brain. The episode most often lasts less than a couple of minutes and y...
Read Article Now Book Mark Article - Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Considerations
If a disease linked to cold agglutinin is suspected, the person needs to be kept warm.
References
Baum SG, Goldman DL. Mycoplasma infections. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 301.
Elghetany MT, Banki K. Erythrocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 33.
Michel M, Jäger U. Autoimmune hemolytic anemia. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 46.
Quanquin NM, Cherry JD. Mycoplasma and ureaplasma infections. In: Cherry JD, Harrison GJ, Kaplan SL, Steinbach WJ, Hotez PJ, eds. Feigin and Cherry's Textbook of Pediatric Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 196.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
-
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 5/4/2022
Reviewed By: Michael M. Phillips, MD, Emeritus Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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