What is the Paul Bunnell (Monospot) test?

The Paul Bunnell, also known as the Monospot test, is a blood test used to detect heterophile antibodies produced during infection with Epstein–Barr virus (EBV), the most common cause of glandular fever.

These antibodies typically appear during the acute phase of infection and help distinguish glandular fever from other causes of prolonged fatigue, sore throat, or viral illness. The test is most useful when symptoms are present and EBV infection is suspected.

It is often requested alongside full blood count and liver function tests to support clinical assessment.

Why do I need a test for Paul Bunnell (Monospot)?

Glandular fever can present with prolonged and non-specific symptoms that overlap with other viral or bacterial infections. The Paul Bunnell test helps confirm whether EBV is the likely cause.

This test is particularly useful in adolescents and adults with persistent fatigue, sore throat, swollen glands, or unexplained illness that does not resolve as expected.

You may benefit from this test if you experience:

• Persistent fatigue or exhaustion

• Sore throat lasting more than a few days

• Swollen lymph nodes (neck or armpits)

• Fever or flu-like symptoms

• Enlarged tonsils

• Headaches or body aches

• Unexplained liver enzyme changes

• Suspected glandular fever exposure

Benefits of the Paul Bunnell (Monospot) test

1. Supports diagnosis of glandular fever
   Helps identify EBV-related infection.

2. Detects acute immune response
   Identifies heterophile antibodies produced during active infection.

3. Differentiates EBV from other illnesses
   Helps distinguish glandular fever from bacterial throat infections.

4. Useful in prolonged fatigue assessment
   Supports investigation of persistent tiredness.

5. Aids clinical decision-making
   Helps guide reassurance and appropriate follow-up.

6. Simple blood-based investigation
   Requires only a single blood sample.

7. Complements other blood tests
   Often interpreted alongside FBC and liver markers.

8. Supports infection control awareness
   Helps confirm viral cause and expected recovery course.

Step-by-step – how we offer Paul Bunnell (Monospot) testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic

• Attend your appointment

• A qualified clinician or phlebotomist collects your blood sample

• Sample is sent to the laboratory for analysis

At-home or hotel testing (+£60)

• A qualified phlebotomist visits your home or hotel

• Blood sample collected in a comfortable, familiar setting

• No clinic visit or travel required

Both services are available UK-wide.

Your Paul Bunnell (Monospot) results explained

Negative result

A negative result means heterophile antibodies were not detected. This suggests glandular fever is unlikely at the time of testing, although early infection cannot always be excluded.

If symptoms persist, further EBV-specific antibody testing may be considered.

UK reference interpretation:

• Negative: Not detected

Positive result

A positive result indicates the presence of heterophile antibodies, supporting a diagnosis of glandular fever due to EBV infection.

This typically reflects an active or recent infection.

UK reference interpretation:

• Positive: Detected

Indeterminate / borderline result

Occasionally, results may be unclear, particularly early in infection. In such cases, additional EBV antibody testing may help clarify infection status.

UK reference interpretation:

• Borderline: Equivocal