Mononucleosis (Mono) Tests

Urgent safety information

Mono can cause an enlarged spleen, which could rupture and cause a medical emergency. To try to protect the spleen, providers recommend avoiding intense exercise and contact sports until you fully recover (about a month).

Why this test may be ordered

• To help diagnose a mono infection when symptoms are present, especially if symptoms are severe or lasting.
• To distinguish mono from other illnesses with similar symptoms (e.g., strep throat, flu).
• To determine if an EBV infection is recent or past.

Preparation and collection

You don't need any special preparations for a fingertip blood test or blood test from a vein.

You will need to provide a sample of blood from your fingertip or a vein. Both types of tests are quick, usually taking less than five minutes.

There is very little risk to having a fingertip blood test or blood test from a vein. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

Understanding results

While there is no cure for mono, you can take steps to relieve symptoms. Mono usually goes away on its own within a few weeks. Fatigue may last a bit longer.

• Monospot positive: If your monospot test result is positive, it may mean you or your child has mono. Limitation: If you have a bacterial infection along with mono, you should not take penicillin antibiotics like ampicillin or amoxicillin. Next step: If you have questions about your results or treatment for mono, talk to your provider.
• Monospot negative: If it is negative, but you or your child still have symptoms, your provider will probably order an EBV antibody test. Limitation: But this test has a high rate of false negatives. Next step: If the monospot test is negative, but you or your child still have symptoms, your provider will probably order an EBV antibody test.
• EBV antibody negative: If your EBV test is negative, it means you don't currently have an EBV infection and were never infected with the virus. Limitation: A negative result means your symptoms are probably caused by another disorder. Next step: If you have questions about your results or treatment for mono, talk to your provider.
• EBV antibody positive: If your EBV test is positive, it means EBV antibodies were found in your blood. Limitation: This allows your provider to find out whether you were infected recently or in the past. Next step: If you have questions about your results or treatment for mono, talk to your provider.

• The monospot test has a high rate of false negatives – a negative result does not rule out mono.
• EBV antibody test results must be interpreted in the context of your symptoms and medical history.
• Test results are not diagnostic alone; your healthcare provider will interpret them along with your symptoms.

What to do next

But don't give aspirin to children or teens because it may cause Reye syndrome, a serious, sometimes fatal, disease that affects the brain and liver. If you have questions about your results or treatment for mono, talk to your provider.

• What are my specific test results?
• Do I need additional testing based on these results?
• What steps can I take to manage symptoms if I have mono?
• When can I safely return to sports or intense exercise?

Evidence source

Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.

U.S. National Library of Medicine: Mononucleosis (Mono) Tests

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