Skip to main content Skip to navigation

Febrile/cold agglutinins Test – Indications, Procedure, Results

Last updated: February 8, 2026 Medically reviewed by: RxHarun Orthopedic Specialist Doctor Reading time: 3 min read

Agglutinins are antibodies that cause the red blood cells to clump together.

  • 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

A blood sample is needed .

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.

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
  • Inflammatory bowel disease
  • Lymphoma
  • Systemic lupus erythematosus
  • Use of certain medicines, including methyldopa, penicillin, and quinidine

Cold agglutinins may occur with:

  • Infections, especially mononucleous and mycoplasma pneumonia
  • Chicken pox (varicella)
  • Cytomegalovirus infection
  • Cancer, including lymphoma and multiple myeloma
  • Listeria monocytogenes
  • Systemic lupus erythematosus
  • Waldenström macrogolulinemia

Risks

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)

Considerations

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

 

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area later with a custom field named _rx_references.

Related Articles

Hemoglobin A1c Test

November 6, 202521 min read0 views

The hemoglobin A1c test—also known as glycated hemoglobin, glycosylated hemoglobin, HbA1c, or simply A1c—is used to measure an individual’s glucose control levels. The test shows average…

Read more

Orbital Decompression Surgery

August 18, 202518 min read0 views

Orbital decompression is an operation to make more room inside the eye socket. The eye socket is called the “orbit.” It is a cone-shaped…

Read more

Olfactory Nerve Disorders

May 8, 20248 min read0 views

Olfactory nerve disorders affect our sense of smell. This can impact our ability to enjoy food, detect danger like gas leaks, or even notice…

Read more

Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.