TB QuantiFERON®

What is the TB Quantiferon® Test?

The TB Quantiferon® test is an interferon-gamma release assay (IGRA) that measures the immune system’s response to Mycobacterium tuberculosis. It detects whether white blood cells release interferon-gamma when exposed to TB-specific antigens.

Unlike the traditional tuberculin skin test, this blood test is not affected by prior BCG vaccination and does not require a return visit for reading results. It is used to help identify both latent TB infection and possible active TB when interpreted alongside clinical findings.

The test is widely used in healthcare, occupational screening, immigration assessments, and clinical investigations.

Why do I need a TB Quantiferon® test?

Tuberculosis infection can exist in a latent form without symptoms but still pose future health risks. Identifying infection early is important for individual health, public safety, and workplace or immigration requirements.

You may need this test if you:

• Have been in contact with someone diagnosed with TB
• Require TB screening for work, visa, or study purposes
• Have symptoms such as persistent cough, weight loss, or night sweats
• Are immunocompromised or planning immunosuppressive therapy
• Have a history of travel or residence in high TB prevalence regions
• Have an abnormal chest X-ray requiring further investigation
• Need TB clearance for healthcare or occupational screening

Testing helps determine TB exposure and guides further assessment when required.

Benefits of the test

1. Accurate TB infection detection
   Identifies immune response specific to TB bacteria.
2. Not affected by BCG vaccination
   Avoids false positives seen with skin testing.
3. Single blood test
   No follow-up visit needed for result interpretation.
4. Useful for latent TB screening
   Detects infection even without symptoms.
5. Widely accepted for occupational screening
   Used for healthcare, visa, and employment checks.
6. Objective laboratory result
   Provides clear positive, negative, or indeterminate outcomes.
7. Suitable for immunocompromised patients
   Often preferred over skin testing in high-risk groups.
8. Supports public health risk assessment
   Helps identify individuals needing further evaluation.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic
• Attend your appointment
• A clinician draws a blood sample
• Sample is sent to the laboratory
• Results are issued once analysis is complete

Home or hotel visit (+£60, UK-wide)

• Book a mobile phlebotomist
• Blood sample taken at your home or hotel
• No need to travel to a clinic
• Sample securely transported to the laboratory

Your results explained

Negative (no TB infection detected)

• No significant interferon-gamma response
• UK standard: Negative
• Suggests no evidence of TB infection

Positive (TB infection detected)

• Interferon-gamma response above diagnostic threshold
• UK standard: Positive
• Indicates TB infection (latent or active) and requires clinical correlation

Indeterminate result

• Inadequate immune response or technical factors
• UK standard: Indeterminate
• May occur in immunosuppression or sample-related issues