Latent Tuberculosis Infection (LTBI) Testing

Latent TB testing aims to identify individuals infected with the bacteria which causes TB but who are not currently sick and cannot spread the infection, though they are at risk of developing active TB later.

Tuberculosis (TB) is an infection caused by bacteria. It mainly affects the lungs, but it can affect any part of the body, including lymph nodes (glands), bones and the brain causing meningitis.

TB is spread when a person with TB in their lungs or throat coughs or sneezes.

When people talk about TB, they usually mean ‘active TB disease’. This means that the bacteria are multiplying in your body, making you ill and you could pass TB on to other people.

You may also hear the term “latent TB” which means the bacteria are inactive - sometimes it is called sleeping TB. People with latent TB are not unwell and cannot pass it on to other people. Many people who have latent TB infection never develop TB disease. In these people the TB bacteria remain inactive for a lifetime without causing disease. But in other people the bacteria become active, multiply and can cause disease.    

Anyone can get TB, but people are at higher risk if they have other conditions that may make them more vulnerable to infections. For example, if you have diabetes,  or HIV or had treatments for conditions such as cancer, rheumatoid arthritis, or an organ transplant.

There are different reasons that you may be offered screening for active or latent TB. These include:

• If you have been in contact with someone who has TB in the lungs. Sometimes you may not know that you had contact with TB, especially if the contact occurred happened at work or college. If you do receive an invite to be screened, it is important  to go to the appointment. It is important to attend your appointment.
• If you have a certain condition, like rheumatoid arthritis or Crohn’s where you need to have biologic treatments.
• As part of an occupational health screening.
• If you have recently arrived from a country where there is a high rate of TB, your GP may invite you for a TB test.

If you have arrived from a country where there is a high rate of TB, your GP may invite you for a latent TB test. Even if you have had your BCG vaccine or have been tested for active TB, you can still have latent TB. Chest X-ray does not detect latent TB. If you are unsure and think you might be eligible for a test, please contact your GP. 
 

It will involve a quick blood test and a few simple questions. This can be done by your GP. Testing and treatment is completely free and confidential. 

Your nurse or doctor will let you know when to expect your results and what will happen next.

If your blood test shows that you have latent TB, your doctor or nurse will offer you antibiotic treatment. The treatment will last three or six months. Your doctor will explain about your care and why it is important to finish your treatment. As with all medications, there is a small risk of side effects which your doctor or nurse can help you manage.