Mono

Also known as: Mononucleosis spot test; Mononuclear heterophile test; Heterophile antibody test; Monospot

Formal name: Heterophile antibody titer

The Test Sample

What is being tested?

Mononucleosis, or mono, refers to an infection caused by the Epstein-Barr virus (EBV). The infection is characterized by a particular set of symptoms that most often affects adolescents. People who have mono often have a fever, sore throat, swollen glands, and fatigue. Many will also have an enlarged spleen and a few may have an enlarged liver. Symptoms of the infection usually arise about one month after infection and may last for several weeks. The associated fatigue may last for several months. Mono is usually a self-limiting condition; the symptoms resolve without any specific treatment.

EBV is very common. According to Centers for Disease Control and Prevention (CDC), up to 95% of people in the United States will have been infected by EBV by the time they are 40 years old. It is spread from person to person through saliva during close contact. Most of the time, the EBV infection occurs in childhood and causes few or no symptoms, but if first exposure to the virus occurs in adolescence, it can cause symptoms associated with infectious mononucleosis (mono) in about half of those infected. Mono can affect anyone at any age, but its prevalence is highest in populations of young people, such as are found at high schools, colleges, or in the military.

The mono test detects heterophile antibodies, which are made by the body in response to an infection by EBV. About 70% to 80% of those with mono produce heterophile antibodies. These proteins are not specific for EBV but, when found in adolescents in conjunction with mono symptoms, they help diagnose infectious mononucleosis. Mono is also characterized by the presence of atypical white blood cells (usually reported as reactive lymphocytes) as seen on a blood smear and by the presence of EBV antibodies in an infected person.

How is the sample collected for testing?

A blood sample is drawn by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.