There are several methods of confirming whether mononucleosis is present in an individual, including antibodies tests that detect the Epstein-Barr virus; when these are not present, it is safe to say that mono is gone, according to MedicineNet. Most doctors just look for a cessation of symptoms to confirm that the treatment for mono was successful.
Mono is diagnosed by blood tests that show an increase in the number of white blood cells in the body. The white blood cells, or lymphocytes, have an unusual look when microscopically examined.
Heterophile antibody tests, including Monospot, can be useful in diagnosing mono. These types of tests rely on the immune system to make bodies that fight off the virus that causes mono. These antibodies are sometimes not detectable until the third week of the illness. Another test used in the diagnosis is a blood chemistry test; this test can reveal abnormalities and inflammation in the functionality of the liver.
Those infected with the Epstein-Barr virus may have particles of the virus in their saliva for up to 18 months after becoming infected. Infections of this sort are referred to as chronic EBV infections or as chronic mono when the symptoms are noticed for longer than 6 months.