How is TB diagnosed?

Your doctor may refer you to a TB specialist for testing and treatment if they think you have TB.

Diagnosing active TB of the lungs can be difficult and you will usually need several tests. The most important tests are a chest X-ray and examining a sample of your phlegm.

If you might have active TB in another part of your body, you will usually have a small sample taken from the part affected. For example, if you have enlarged lymph glands in your neck, your doctor will take a sample using a small needle, often guided by an ultrasound machine. It’s not painful – you’ll have a local anaesthetic. You’ll also have a chest X‑ray to see if you have TB in your lungs as well.

If you have been in contact with someone who has TB in their lungs, you might be offered tests to see if you have latent or active TB. Tests include:

Next: Can I infect other people with TB?

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Last medically reviewed: September 2017. Due for review: September 2020

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.