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How Do Doctors Test for Mono?

I think I have mono. What kinds of tests will the doctor do?

Sometimes, doctors don’t do any tests for mono — the doctor may suspect that you have mono from your medical history and doing a physical exam. A lot of doctors will do blood tests to confirm mono, though.

If someone has symptoms of mono, the doctor may order a complete blood count to look at the lymphocytes, a type of white blood cell that shows specific changes when a person has mono.

A doctor may also order a blood test called a monospot. If the monospot is positive, it’s pretty accurate, meaning that the person likely has mono. But it can sometimes take a couple of weeks after someone first gets mono for the monospot to detect the infection. So if you haven’t had mono long, a monospot test might be negative even though you actually have mono.

If a doctor still thinks you have mono after a monospot comes back negative, he or she may want to repeat the test a week or so later. Or your doctor may order a blood test that looks for specific antibodies to Epstein-Barr virus (the virus that causes mono). This test can tell whether someone has had mono very recently, had it in the distant past, or never had it at all.

If you have a sore throat that’s very red with white patches, the doctor may want to test for strep throat. For this test, the doctor will wipe some mucus from the back of your throat with a cotton swab, then send it to a lab for testing.

Reviewed by: Elana Pearl Ben Joseph, MD
Date reviewed: February 2013

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