What is the Q Fever (Coxiella burnetii) Antibodies test?

The Q Fever Antibodies test measures antibodies produced by the immune system in response to infection with Coxiella burnetii, a bacterium that causes Q fever. This organism is commonly transmitted from animals, particularly livestock, through inhalation of contaminated dust or aerosols.

The test typically detects antibodies to Phase I and Phase II antigens, which help differentiate between acute and chronic infection. Q fever can present with a wide range of symptoms, from mild flu-like illness to severe complications affecting the lungs, liver, or heart.

This blood test is used to support diagnosis when exposure or symptoms suggest Q fever infection.

Why do I need a test for Q Fever?

Q fever can be difficult to diagnose because symptoms are often non-specific and may resemble other infections. Antibody testing helps confirm exposure and identify whether infection is recent, past, or potentially chronic.

Testing is particularly important for individuals with occupational exposure to animals or unexplained prolonged illness.

You may benefit from this test if you experience:

• Persistent fever or flu-like symptoms

• Severe fatigue lasting weeks or months

• Pneumonia or unexplained respiratory symptoms

• Hepatitis or abnormal liver function tests

• Night sweats or weight loss

• History of livestock or farm exposure

• Occupational exposure (veterinary, farming, abattoir work)

• Suspected endocarditis of unknown cause

Benefits of the Q Fever Antibodies test

1. Identifies exposure to Coxiella burnetii
   Confirms immune response to Q fever infection.

2. Supports diagnosis of unexplained fever
   Useful when routine infection tests are negative.

3. Helps differentiate acute and chronic infection
   Phase-specific antibodies guide clinical interpretation.

4. Relevant for occupational health screening
   Important for high-risk professions.

5. Supports investigation of chronic fatigue
   Q fever may cause long-lasting symptoms.

6. Assists in endocarditis evaluation
   Chronic Q fever is a known cause of culture-negative endocarditis.

7. Non-invasive infectious disease assessment
   Requires only a blood sample.

8. Guides further clinical follow-up
   Helps determine need for specialist referral.

Step-by-step – how we offer Q Fever Antibodies testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic

• Attend your appointment

• Blood sample collected by a qualified clinician or phlebotomist

• 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 Q Fever Antibodies results explained

Negative antibodies

Negative results suggest no evidence of current or past Q fever infection at the time of testing. Early infection cannot be fully excluded if exposure was recent.

UK reference interpretation:

• Negative: Not detected

Phase II antibodies detected (acute infection pattern)

Raised Phase II antibodies are typically associated with recent or acute Q fever infection. This pattern is often seen in symptomatic individuals with fever or respiratory illness.

Clinical correlation is essential.

UK reference interpretation:

• Acute pattern: Phase II antibodies detected

Phase I antibodies detected (chronic infection pattern)

Elevated Phase I antibodies suggest chronic Q fever infection, which may involve persistent infection of the heart valves, blood vessels, or other tissues.

Further specialist evaluation is usually required.

UK reference interpretation:

• Chronic pattern: Phase I antibodies detected