Mononucleosis tests are blood tests to look for antibodies that indicate mononucleosis (mono), which is 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 generally 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.

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

No special preparation is required before having this test.

Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will indicate. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?) .

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 fingertip sample, the health professional taking the sample will:

• Clean your hand with soap and warm water or an alcohol swab.
• Massage your hand without touching the puncture site.
• Puncture the skin on the side of your middle or ring finger with a small instrument called a lancet.
• Wipe away the first drop of blood.
• Place a small tube called a capillary tube on the puncture site and collect a small amount of blood.
• Put a gauze pad or cotton ball over the puncture site as the tube is removed.
• Put pressure on the site and then put on a bandage.

Blood test from a vein

The health professional taking a sample of your blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Put a gauze pad or cotton ball over the needle site as the needle is removed.
• Put pressure on the site and then put on a bandage.