Blood test
Monospot Test
A monospot test looks for antibodies produced during glandular fever (infectious mononucleosis), usually caused by the Epstein-Barr virus.
Quick answer
Monospot Test: what it is and what the results mean
The monospot test detects heterophile antibodies that the body makes in response to infection with the Epstein-Barr virus, the usual cause of glandular fever. More specific EBV antibody tests are sometimes used instead.
- Why it is done: It is used to help diagnose glandular fever in people with a sore throat, fever, swollen glands and tiredness, particularly teenagers and young adults, when the diagnosis is unclear.
- Understanding results: A positive result supports glandular fever, while a negative result does not fully exclude it, especially early on.
What it is
The monospot test detects heterophile antibodies that the body makes in response to infection with the Epstein-Barr virus, the usual cause of glandular fever. More specific EBV antibody tests are sometimes used instead.
Why it is done
It is used to help diagnose glandular fever in people with a sore throat, fever, swollen glands and tiredness, particularly teenagers and young adults, when the diagnosis is unclear.
What to expect
It is a simple blood test from a vein in the arm. It may be negative early in the illness, so it is sometimes repeated or replaced by specific EBV antibody tests.
Understanding the results
A positive result supports glandular fever, while a negative result does not fully exclude it, especially early on. Results are interpreted with symptoms and, if needed, more specific virus tests.
Good to know
Risks and limitations
It is a safe blood test but can give false negatives early in the illness and occasional false positives, so it is used alongside the clinical picture and sometimes confirmed with EBV-specific tests.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Monospot Test: frequently asked questions
Why might my monospot test be negative if I have glandular fever?
The antibodies it detects can take a week or two to appear, so an early test may be negative. It can be repeated later or replaced by more specific EBV antibody tests.
How is glandular fever treated?
There is no specific cure; treatment focuses on rest, fluids and pain relief while the infection clears. The blood test mainly confirms the diagnosis and reassures about the cause.
Related tests
Other blood test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- British Society for Haematology / relevant professional body
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