Lifespan's A - Z Health Information Library

Sometimes, when the body reacts to an infection, antibodies are made that have nothing to do with the germ. These are called heterophil antibodies.

The heterophil agglutination test is a way to detect two antibodies in the blood that indicate infection with the Epstein-Barr virus (EBV).

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children:

The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.

No special preparation is necessary.

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

The appearance of heterophil antibodies may indicate one of several infections, but is most commonly used to diagnose infectious mononucleosis, an illness caused by Epstein-Barr virus.

No heterophil antibodies are detected.

The presence of heterophil antibodies usually indicates infectious mononucleosis, although the interpretation of results may vary, depending on how the test is done.

Risks associated with having blood drawn are slight:

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a minimal risk any time the skin is broken)
• Multiple punctures to locate veins

Veins and arteries vary in size from one patient 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.