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.
A blood sample is needed.
No special preparation is necessary.
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.
The mononucleosis spot test is done when symptoms of mononucleosis are present. Common symptoms include:
This test looks for antibodies called heterophile antibodies, which form in the body during the infection.
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.
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:
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:
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Johannsen EC, Kaye KM. Epstein-Barr virus (infectious mononucleosis, Epstein-Barr virus-associated malignant diseases, and other diseases). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 138.
Weinberg JB. Epstein-Barr virus. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 281.BACK TO TOP
Review Date: 3/10/2022
Reviewed By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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