Mononucleosis spot test
Monospot test; Heterophile antibody test; Heterophile agglutination test; Paul-Bunnell test; Forssman antibody test
The mononucleosis spot test looks for 2 antibodies in the blood. These antibodies appear during or after an infection with the virus that causes mononucleosis, or mono.
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...
How the Test is Performed
A blood sample is needed.
Blood sample
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
How to Prepare for the Test
No special preparation is necessary.
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 or a slight bruise. This soon goes away.
Why the Test is Performed
The mononucleosis spot test is done when symptoms of mononucleosis are present. Common symptoms include:
Mononucleosis
Mononucleosis, or mono, is a viral infection that causes fever, sore throat, and swollen lymph glands, most often in the neck.
- Fatigue
- Fever
- Large spleen (possibly)
- Sore throat
- Tender lymph nodes along the back of the neck
This test looks for antibodies called heterophile antibodies. These form in the body during the infection.
Normal Results
A negative test means there were no heterophile antibodies detected. Most of the time this means you do not have infectious mononucleosis.
Sometimes, the test may be negative because it was done too soon (within 1 to 2 weeks) after the illness started. Your health care provider may repeat the test to make sure you do not have mono.
What Abnormal Results Mean
A positive test means heterophile antibodies are present. These are most often a sign of mononucleosis. Your provider will also consider other blood test results and your symptoms. A small number of people with mononucleosis may never have a positive test.
The highest number of antibodies occurs 2 to 5 weeks after mono begins. They may be present for up to 1 year.
In rare cases, the test is positive even though you do not have mono. This is called a false-positive result, and it may occur in people with:
- Hepatitis
- Leukemia or lymphoma
- Rubella
- Systemic lupus erythematosus
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Toxoplasmosis
Toxoplasmosis
Toxoplasmosis is an infection due to the parasite Toxoplasma gondii.
Risks
Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood buildup under the skin)
- Infection (a slight risk any time the skin is broken)
References
Johannsen EC, Kaye KM. Epstein-Barr virus (infectious mononucleosis, Epstein-Barr virus--associated malignant diseases, and other diseases). In: Bennett JE, Dolin R, Blase MJ, eds. Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases . 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 141.
Lindemann JC. Fatigue. In: Bope ET, Kellerman RD, eds. Conn's Current Therapy 2016 . Philadelphia, PA: Elsevier; 2016:section 1.
Schooley RT. Epstein-Barr virus infection. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 377.
Weber R. Pharyngitis. In: Bope ET, Kellerman RD, eds. Conn's Current Therapy 2016 . Philadelphia, PA: Elsevier; 2016:section 1.
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Mononucleosis, photomicrograph of cells - illustration
This so-called "Downy cell" is typical of lymphocytes infected by EBV (Epstein Barr Virus) or CMV (Cytomegalovirus) in infectious mononucleosis. Downy cells may be classified as types I, II, or III. This is a type II Downy cell.
Mononucleosis, photomicrograph of cells
illustration
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Mononucleosis - view of the throat - illustration
Infectious mononucleosis causes a sore throat, enlarged lymph nodes, and fatigue. The throat may appear red and the tonsils covered with a whitish material. Mononucleosis and severe streptococcal tonsillitis appear quite similar. Unless there are other findings to suggest mononucleosis, a throat culture and blood studies may be necessary to make an accurate diagnosis.
Mononucleosis - view of the throat
illustration
-
Mononucleosis, photomicrograph of cells - illustration
This so-called "Downy cell" is typical of lymphocytes infected by EBV (Epstein Barr Virus) or CMV (Cytomegalovirus) in infectious mononucleosis. Downy cells may be classified as types I, II, or III. This is a type II Downy cell.
Mononucleosis, photomicrograph of cells
illustration
-
Mononucleosis - view of the throat - illustration
Infectious mononucleosis causes a sore throat, enlarged lymph nodes, and fatigue. The throat may appear red and the tonsils covered with a whitish material. Mononucleosis and severe streptococcal tonsillitis appear quite similar. Unless there are other findings to suggest mononucleosis, a throat culture and blood studies may be necessary to make an accurate diagnosis.
Mononucleosis - view of the throat
illustration
Review Date: 3/13/2016
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.