What Is a Heterophile Antibody?

Heterophile antibodies refer to antibodies the body produces as part of an immune response to an infection but that are not related to the germ. Since people often produce heterophile antibodies while infected with mononucleosis, a viral infection caused by the Epstein-Barr virus, some doctors diagnose mononucleosis based on the presence of heterophile antibodies.

Features

• Many patients produce heterophile antibodies within a week of contracting mononucleosis, according to the University of Maryland Medical Center. Heterophile antibody production are highest two to five weeks after the infection begins.

Detection

• Doctors detect heterophile antibodies by performing a mononucleosis spot test on a blood sample from the patient.

Considerations

• About 10 percent of patients with mononucleosis never develop heterophile antibodies, according to the University of Michigan, so a mononucleosis spot test cannot definitively determine the presence of mononucleosis. In rare cases, some patients who produce heterophile antibodies may actually have a different illness, such as hepatitis, leukemia, lymphoma or Hodgkin's disease.