Mononucleosis (Mono) Tests

Urgent safety information

If you experience sudden sharp pain in the left upper abdomen, seek emergency medical care immediately. Mono can cause an enlarged spleen, which may rupture and cause a medical emergency.

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.

Blood sample from a fingertip (prick) or from a vein in the arm.

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. The monospot test has a high rate of false negatives, which is an important limitation to discuss with your provider.

Understanding results

Results are typically available within an hour for the monospot test. EBV antibody test results may take longer. Your healthcare provider will explain what the results mean for you.

• Monospot Negative: You may not have mono, but the test can miss the infection. Limitation: High false negative rate; may need follow-up with EBV antibody test. Next step: If negative but symptoms persist, your provider may order an EBV antibody test.
• Monospot Positive: It may mean you have mono. Limitation: Positive result suggests mono, but the test does not distinguish between different viruses or timing of infection. Confirmatory testing with EBV antibody test may be needed. Next step: Your provider will likely order an EBV antibody test to confirm and determine if the infection is recent or past.
• EBV Antibody Negative: You do not currently have an EBV infection and were never infected with EBV. Your symptoms are probably caused by another disorder. Limitation: A negative result does not rule out all causes of mono-like symptoms; other viruses may be responsible. Next step: Your provider will look for other causes of your symptoms.
• EBV Antibody Positive: EBV antibodies were found. Specific types show whether you were infected recently or in the past. Limitation: The test shows past or recent EBV infection, but management depends on symptoms and organ involvement. Next step: Your provider will discuss the results and recommend management based on your symptoms and the timing of infection.

• 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

If you are diagnosed with mono: Get plenty of rest, drink lots of fluids, and use lozenges to soothe a sore throat. Take over-the-counter medicines for pain and fever, but do not give aspirin to children or teens (risk of Reye syndrome). Antibiotics are not used to treat viral mono. If you also have a bacterial infection, do not take penicillin antibiotics (e.g., ampicillin, amoxicillin) as they may cause a rash. Avoid intense exercise and contact sports for about a month to protect the spleen. If you have severe symptoms, your provider may recommend additional treatment based on organ involvement. Follow up with your healthcare provider for any questions or if symptoms worsen.

• 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

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