What should you know about two TB tests?

The Mantoux test involves placing a small amount of testing material just under the skin. A clinician checks the area after the scheduled interval for a measured skin reaction. An IGRA uses a blood sample and checks how immune cells respond to TB proteins in the laboratory. Neither test can by itself show whether infection is active, where it is located, or whether symptoms are caused by TB. A positive result usually leads to a clinical review, which may include a chest X-ray and other tests. A negative result lowers the likelihood of infection but may not settle the question when exposure was recent or the immune system is weakened.

Attend the follow-up appointment for a Mantoux reading if that is the test chosen; missing the reading can make the result unusable. Tell the clinician about previous TB infection, BCG vaccination, medicines that affect immunity, recent exposure, and symptoms such as a persistent cough, fever, night sweats, or unexplained weight loss. Do not interpret a positive test as proof that you can pass TB to others. If active disease is suspected, follow the recommended imaging and laboratory plan and avoid delaying review.

Seek prompt medical advice after close contact with someone who has infectious TB, especially if you develop a persistent cough, fever, night sweats, marked tiredness, or weight loss. Seek urgent help for severe breathing difficulty, coughing blood, confusion, or a rapid deterioration. A healthcare professional can decide whether testing should be repeated or paired with further assessment.

Ask which test is appropriate for your age, exposure history, vaccination history, and immune health. You can also ask when a result is reliable after exposure, what a positive result means in your situation, and whether a chest X-ray or additional TB assessment is needed.