They test for mononucleosis primarily using blood tests that detect antibodies produced in response to the Epstein-Barr virus (EBV), which causes mono. The most common test is the Monospot test (heterophile antibody test), which looks for heterophile antibodies in the blood. This test is quick and involves drawing a blood sample, but it can have false negatives, especially early in the illness. If the Monospot test is negative but symptoms persist, doctors often use more specific EBV antibody tests to detect different types of antibodies that indicate recent or past infection. Additional tests may include a complete blood count (CBC) to check for elevated white blood cells and a throat culture to rule out other infections like strep throat.
Common Mono Tests:
- Monospot Test (Heterophile Antibody Test): Detects heterophile antibodies that appear during infection. Results come quickly, but it may be negative in the first 1-2 weeks of illness or in young children.
- EBV Antibody Test: More specific test measuring antibodies against EBV, which helps determine the stage of infection (recent, past, or chronic).
- Complete Blood Count (CBC): Checks for elevated white blood cells, which indicate infection.
- Throat Culture: Sometimes used to exclude other causes of sore throat similar to mono.
How the Tests Are Done:
- Blood is drawn from a vein or fingerstick.
- The Monospot test is rapid, giving results usually within an hour.
- EBV antibody tests take longer, sometimes several days.
When Testing is Done:
- Testing is usually recommended if symptoms like fatigue, fever, sore throat, swollen lymph nodes, or enlarged spleen are present.
This testing approach helps confirm diagnosis of mono and differentiate it from other illnesses with similar symptoms.
