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Mononucleosis Tests

Test Overview

Mononucleosis tests are blood tests to look for antibodies that indicate mononucleosis (mono), which is usually caused by the Epstein-Barr virus (EBV). The antibodies are made by the immune system to fight an infection.

Mono tests include:

  • Monospot test (heterophil test). This quick screening test detects a type of antibody (heterophil antibody) that forms during certain infections. A sample of blood is placed on a microscope slide and mixed with other substances. If heterophil antibodies are present, the blood clumps (agglutinates). This result usually indicates a mono infection. Monospot testing can usually detect antibodies 2 to 9 weeks after a person is infected. It typically is not used to diagnose mono that started more than 6 months earlier.
  • EBV antibody test. For this test, a sample of blood is mixed with a substance that attaches to antibodies against EBV. A series of tests can detect different types of antibodies to help determine whether you were infected recently or sometime in the past.

Why It Is Done

The monospot test is done to help diagnose a recent mono infection.

Epstein-Barr virus (EBV) antibody testing is also done to help diagnose mono. The EBV antibody test can help determine whether you have ever been infected with the virus and whether the infection has been recent.

EBV antibody testing is usually done when you have symptoms of infectious mononucleosis and a monospot test result is negative. EBV antibody testing may also be done to check for antibodies to EBV when a person has a disease or uses medicine that causes problems with the immune system.

How To Prepare

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How It Is Done

The monospot test is done on a small sample of blood taken from your fingertip or from a vein. The Epstein-Barr antibody test is done on a blood sample taken from your vein.

Blood test from a finger stick

For a finger-stick sample, the health professional will puncture the skin on your middle or ring finger with a small tool called a lancet. Then they'll collect a small amount of blood.

Blood test from a vein

A health professional uses a needle to take a blood sample, usually from the arm.

Watch

How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Results

Monospot test

The results of a monospot test are usually ready within 1 hour.

Monospot test

Normal (negative):

The blood sample does not form clumps (no heterophil antibodies are detected).

Abnormal (positive):

The blood sample clumps (heterophil antibodies are detected). If the blood sample clumps, you probably have mono.

Epstein-Barr antibody testing

The results of an EBV antibody test are usually ready within 3 days.

The results of the antibody test to detect Epstein-Barr virus (EBV) are usually reported as positive (antibodies are present) or negative (antibodies are not present).

The EBV antibody test can also detect the type of antibodies (immunoglobulins) present in the blood. The type of antibody shows whether the infection is recent or old.

EBV antibody test

Normal (negative):

No IgM antibody against EBV is present.

If the antibody IgG is present, it may mean that you have been exposed to EBV in the past.

Abnormal (positive):

The antibody IgM against EBV is present.

Credits

Current as of: September 23, 2020

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Caroline S. Rhoads MD - Internal Medicine