What laboratory test is commonly used to diagnose infectious mononucleosis?

The heterophile antibody test is the most commonly used laboratory test for diagnosing infectious mononucleosis, primarily caused by the Epstein-Barr virus. This test detects the presence of heterophile antibodies, which are typically produced in response to the viral infection. The classic test used for this purpose is the Monospot test, which is rapid and simple to perform, providing quick results.

In cases of infectious mononucleosis, individuals often present with symptoms such as fever, sore throat, and lymphadenopathy, and the presence of heterophile antibodies correlates with these clinical manifestations. While additional tests can provide more information about the infection or help rule out other conditions, the heterophile antibody test remains the cornerstone of mononucleosis diagnosis due to its specificity and quick turnaround time.