Tuberculosis Screening

A tuberculosis screening test checks to see if you have the bacteria (germs) that cause tuberculosis (TB) in your body. TB is a bacterial infection that mainly attacks the lungs. But it can also affect other parts of the body, including the brain, spine, and kidneys.

TB germs cause two types of conditions: Inactive (latent) TB infection happens when you have TB germs in your body, but you're not sick because the germs aren't active. This means you don't have symptoms, and you can't spread the disease to others. However, the germs could start to multiply and make you sick in the future.

So, inactive TB infection is usually treated to prevent you from getting sick with active TB.; Active TB disease means that TB germs are actively growing in your body and making you sick. If TB germs grow in your lungs or throat, you can spread the disease to other people by coughing or sneezing. Antibiotics can almost always cure active TB, but without treatment, it can cause serious illness or even death.; There are two types of TB screening tests that are used to detect TB: a TB skin test (also called a Mantoux test) and a TB blood test (also called an IGRA test).

Your health care provider or your local health department can let you know which test is best for you.

Why this test is done

You may need a TB screening test if you:

• Were exposed to someone with active TB disease.
• Are starting a new job or entering a new school.
• Have a high risk of exposure.

Your risk of exposure is higher if you:

• Work in health care.
• Work or live in a place where TB is more common, such as jails, nursing homes, and shelters for people without homes.
• Were born in or often travel to countries where TB disease is common.
• Are having an organ transplant.
• Use illegal drugs that are injected with needles.
• Are receiving treatments for rheumatoid arthritis or Crohn's disease.
• Have a weakened immune system or a health condition that increases your risk of getting active TB. These conditions include diabetes or diseases that weaken your immune system such as HIV.

HIV can especially put you at higher risk for TB. This is because HIV weakens the immune system and so makes it harder for your body to fight off the bacteria that cause TB. Having HIV can also increase the risk that an inactive TB infection becomes active TB disease.

Getting treatment for inactive TB can, however, prevent this risk.

You may need a TB test if you have symptoms of an active TB disease, including:

• A cough that lasts longer than three weeks.
• Coughing up blood or sputum (a thick mucus from the lungs).
• Chest pain.
• Night sweats (heavy sweating during sleep).
• Losing weight without trying.
• Loss of appetite.
• Fever.
• Weakness or fatigue.

How to prepare

You don't need any special preparations for a TB skin or blood test.

Sample type

Blood

Other names for this test

TB test, TB skin test, purified protein derivative (PPD) test, latent TB infection test, Mantoux tuberculin skin test; IGRA test, TB blood test