Skip to main content

You are here


What are the symptoms and how is tuberculosis diagnosed?

On this page, we explain the different symptoms of active TB, and how active and latent TB is diagnosed.

What are the symptoms of TB?

If you develop TB symptoms, this is active TB.

TB can affect any part of your body, not just the lungs. In the UK, just over half of people with active TB have TB in their lungs. The most common symptom of TB in the lungs (pulmonary TB) is a persistent cough. You might cough up phlegm, also called sputum, and it may have blood in it.

TB can affect other parts of your body such as the lymph glands, bones, gut, kidney or brain. The second most common place for TB infection is in the lymph glands, often those in the neck. Lymph glands are small areas in your body that contain white blood cells that can swell up if they’re infected.

TB symptoms

Other possible symptoms of TB are:

  • feeling generally unwell
  • losing weight
  • losing your appetite
  • fever with sweating, particularly at night
  • extreme fatigue

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

Diagnosing active TB of the lungs can be difficult and you will usually need several tests. The most important first tests are a chest X-ray and examining samples of your phlegm. Your doctor may also ask you to have an IGRA.

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.

You should get initial results within a few days. It can take weeks to find out the full results, which show which medicines will be effective.

Diagnosing latent TB

There are some situations where you may need to have a test to check for latent or active TB. For example, if you have been in contact with someone who has TB in their lungs, if you’ve recently spent time in a country where TB levels are high or if you’ve just moved to the UK from a country where TB is common.

In these cases, you should be given information and advice about the need for testing. Your health care professional may suggest having a test when you register as a patient. Tests include:

Next: Can I infect other people with TB? > 

We use your comments to improve our information. We cannot reply to comments left on this form. If you have health concerns or need clinical advice, call our helpline on 03000 030 555 between 9am and 5pm on a weekday or email them.

Download our tuberculosis PDF (73KB)

Last medically reviewed: September 2020. Due for review: September 2023

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.