Latent TB
If you have latent TB, the TB bacteria in your body are ‘asleep’. You will not feel ill, and you cannot pass TB on to others. However, the bacteria might ‘wake up’ in the future, making you ill with active TB. The good news is that latent TB can be treated to prevent this happening.
The only way to find out if you have latent TB is to have a test.
Without treatment for latent TB, there is about a 1 in 10 chance that you will develop active TB in your lifetime. You are more likely to develop active TB in the first five years after you breathe in TB bacteria, though you may not know when that happened.
Watch the video about Latent TB
I have been invited for a latent TB test. What should I do?
You have been invited for a latent TB test because you are at increased risk of becoming ill with TB. There is no need to be worried latent TB can be treated before it can cause active TB, and all testing and treatment for TB is free and confidential for everyone.
There are some reasons why you may be more likely to have latent TB such as:
- If you have settled in the UK in the last five years, came from a country where TB is more common and are aged 16-35 years. You may receive an invitation to have a latent TB test through the Coventry and Warwickshire TB service.
- If you meet the criteria for New Entrant Screening, you can contact the TB service directly on 024 76964169 if you have not received an invitation for screening. This test is different to the x-ray that you may have had as part of your visa application process, which only looked for active TB. Having a test or testing positive for latent TB does not affect your right to be in this country.
- You may be asked to take a test for TB if you have spent a lot of time with someone who has TB – it could be a family member, friend or colleague.
What does a test for latent TB involve?
You may be offered either one of two different tests for latent TB, a TB skin test (known as a TST or Mantoux test) or a blood test (known as an IGRA test).
Skin test: For children who have come into contact with someone with infectious TB, a tiny amount of TB extract is injected under the skin on your forearm. If your body has come into contact with TB, the skin becomes raised and red. You will need to return to the test centre between 48-72 hours later for the doctor or nurse to measure and interpret the results.
Blood test: For adults a small amount of blood is taken from your arm and sent to a laboratory. You will be told when to expect the results.
The person taking the test may also ask some questions to help identify your risk of TB:
- if you were born in, or have strong links to particular countries
- whether you know anyone who has had TB
- if you have any long-term illnesses, such as HIV
- if you currently have any unexplained symptoms.
Latent TB treatment
A course of antibiotic medicine for three months will treat latent TB. The TB specialist nurse will talk you through the treatment and answer any questions you may have. It is important that you take your medicine regularly and complete the full course, to make sure all TB bacteria are removed from your body.
Try to take your TB medicine at least one hour before you eat food or two hours afterwards. You can eat anything you like, but you should avoid drinking alcohol.
Make sure you keep all your clinic appointments and tell your doctor or nurse any side effects you may have, or if you are having trouble to remember to take our medication – they will be able to help.
Prevention is better than cure. About 1 in 10 people with latent TB will develop active TB. And there is no way to know if you will be one of them. It is possible to become ill with active TB many years after you breathe in TB bacteria. Treatment is the only way to remove the TB bacteria from your body.
When I finish my treatment, will I be free of TB forever?
If you complete your treatment as prescribed, your risk of developing active TB is much lower. However, it is possible you could breathe in the TB bacteria again in future. The chances of this are low for most people, but is useful to know the most common symptoms of active TB so you can see your GP if you have any of them:
- a cough which lasts for three weeks or longer
- fever (a high temperature)
- night sweats
- weight loss
- no appetite
- tiredness.