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:
- a simple skin test called the Mantoux test
- a blood test called an interferon gamma release assay (IGRA) that tests if your immune system has been exposed to TB bacteria
- a chest X-ray