What is a TB test?

Frequently Asked Questions:

What is the TB test used for?

If your doctor suspects tuberculosis in your body, he will order a TB test for you. The test is to check for any signs of TB infection. However, the test will not show whether your TB is active or latent. Further investigation is required to determine this.

Understanding the results of the TB test

If your doctor suspects tuberculosis in your body, he will order a TB Test for you. The doctor may also recommend extra tests like a chest x-ray and a sputum check. If your result is negative, then you don’t have an infection. If positive, the doctor will check the active/latent status. Both variants need to be treated, as latent TB can convert into positive and pose serious health threats.

Why do I need a TB test?

You will need a TB test if you have symptoms like persistent cough lasting over three weeks, coughing up blood, fever, fatigue, unexplained weight loss, and chest pain. You will also need a TB test if you are in close contact with someone who has an active tuberculosis infection. You should get a test done if you have recently travelled to countries where TB is common. 

What happens during a TB test?

A TB skin test requires two visits to/from the doctor or the nurse. The first step involves an injection of PPD, a protein that comes from TB bacteria in your skin. Please leave the site uncovered and don’t scratch it. After 2-3 days, the doctor will check for signs of reaction at the injection site like swelling, redness, or any bumps. 

A TB blood test is like any other usual blood test where blood will be drawn from a vein in the arm using a small needle.

How many years do you need a TB test?

If you are a healthcare worker prone to getting exposed to people with TB infection, you will require a TB test quite often, ideally twice a year. If you are a frequent traveller to certain countries where tuberculosis cases are very high, it is wise to take a TB test regularly. 

Why would a doctor do a TB test?

Your doctor will ask you to do a TB test if you have a persistent cough that lasts for more than three weeks. Also, a test is required if you have had close contact with someone who has tested positive for active TB. If you have HIV or a weakened immune system, a TB test might be required. 

What if the TB test is positive?

A positive tuberculosis test result indicates that you have TB germs in your body. Most people who have a positive test result have latent TB infection. The doctor will now advise you to do a chest x-ray, along with sputum sampling. Latent TB can become active at any time; hence treatment is required. In case of active infections, you are contagious and must take all necessary precautions to prevent the spread of the infection. 

How long does a TB test take?

A TB skin test will take a little time, as the PPD injection site needs monitoring to determine the signs of infection. The doctor will check the injection after two or three days. The TB blood test is like any other blood test and will be over in less than 5 minutes. 

Do TB tests hurt?

Both the TB skin and the TB blood test do not hurt as such. You may feel a slight pricking sensation during the skin test as PPD is injected. As blood is collected from your vein using a needle, you may feel a little pain during a TB blood test. There are no side effects for both these tests.

What can you not do during a TB test?

There are no particular restrictions for a TB blood test. For the TB skin test, do not scratch the injection site as this could cause swelling or redness and compromise the interpretation of the test results. There are no dietary restrictions before taking a TB test.

At Yashoda Hospitals, you can Get a free second opinion whenever you require it. So book an appointment today and get your TB test done!