What does a positive TB test mean?

A skin test, such as a Mantoux test, or a blood test such as an IGRA may indicate TB infection. Some people have inactive infection, meaning bacteria are contained and they feel well; others have active disease affecting the lungs or another body area. A previous BCG vaccination can affect some skin-test interpretations, while an IGRA is interpreted differently. The result must be considered with your symptoms, medical history, immune health and possible exposure.

Arrange a clinical review even if you feel healthy. The clinician may ask about cough, fever, night sweats, weight change, past exposure and travel, then request a chest X-ray or other tests. Do not start, stop or share TB medicines without advice. If active TB is suspected, follow instructions about masks, ventilation and contact assessment while testing continues.

Seek urgent medical help for difficulty breathing, coughing blood, severe weakness, confusion or chest pain. Contact a clinician promptly for a cough that persists, fever, night sweats or unexplained weight loss, especially after close contact with someone who has active TB or if your immune system is weakened.

Ask which test was positive, whether the result could reflect previous vaccination or infection, whether you need a chest X-ray, whether you need treatment for inactive infection, and whether household or workplace contacts need assessment.