Just because you have been exposed to TB germs does not mean you will get sick from TB—yet. About one-third of the world’s population has been infected with the germs that cause TB. Most of these people do not get sick right away because their immune systems can fight the germs. In those people, the disease goes to sleep and is called “latent TB.” People with latent TB have no symptoms and cannot make other people sick—but they must still be tested and treated. People with latent TB can develop symptoms and become contagious at any time. Then, they are said to have “TB disease.”

People who are most at risk for developing TB disease are:

• the elderly
• small children
• smokers
• people who already have an immune system problem, such as HIV
• people who do not regularly see a doctor, such as homeless people
• people who live in crowded conditions, such as prisons

You can become infected with TB when you breathe in the tiny droplets of air exhaled by someone who has TB disease when they cough, sneeze, laugh, or sing. TB germs can float in the air for several hours, so it is possible to inhale them even when the sick person is not in the same room as you are.

You cannot catch TB by shaking hands, sharing food or drink, or kissing.

People with latent TB have no symptoms, but they should still be treated. Symptoms of pulmonary TB include:

• coughing that continues for several days
• coughing up blood
• fever, including low-grade, consistent fever
• excessive sweating
• chest pain
• unexplained weight loss
• fatigue

Because these are signs of other diseases, too, you should see a doctor to find out their cause.

You should immediately see your doctor if you have symptoms of TB disease. Your doctor will conduct a physical exam, including checking to see if your lymph nodes are swollen, asking about your health history, and perhaps scheduling a chest X-ray. If your doctor thinks you might have TB, or if you have been exposed to someone who has TB disease, the next step is a medical test.

There are two tests for TB: a skin test and a blood test. The skin test is the most common and less expensive, but it requires two visits to your doctor. If returning for a second visit might be a problem for you, you should ask your doctor if you can take the blood test.

Skin Test

Your doctor or nurse will inject a very small amount (not enough to make you sick) of the protein from TB under your skin. The location of the shot may itch a little, but it is important not to scratch it, as this could make the test result hard to read. You will be told to return to the doctor’s office in either two or three days. At that time, the doctor or nurse will look at the spot where the injection was made to see if it is swollen. A hardened swelling of five or more millimeters is an indication that you could be infected with TB. Five millimeters is about one-quarter of an inch. Redness at the location of the injection is normal and is not a sign of a TB infection.

Sputum Test

Sputum test for two days. This test uses your sputum or tissue sample to grow any TB bacteria that may be there. It tells doctors how infectious you are and also whether your TB is resistant to any antibiotics.

People with latent TB have no symptoms and cannot pass TB to another person. However, it is very important to be treated even if you have no symptoms because you could develop TB disease in the future.

If you have latent TB, you may need to take just one TB drug. If you have TB disease, your doctor will prescribe several medicines, which you will need to take for six months or longer. The four most common TB medicines are:

• isoniazid
• rifampin (Rifadin, Rimactane)

• ethambutol (Myambutol)
• pyrazinamide

Even if you feel better after starting your medicines, you must continue to take your medication exactly as your doctor prescribed. Stopping treatment or skipping doses can make TB resistant to medicines, leading to a very dangerous type of TB called “multidrug-resistant TB” (MDR TB).

To help you complete treatment, your doctor might recommend an approach called “directly observed therapy” (DOT). With DOT, a healthcare professional such as a nurse meets with you every day or several times a week to administer your medication so that you don’t have to remember to take it on your own.

If you are not on DOT, you should make a plan for taking your medicines so that you do not miss a dose. Some tips to help you remember to take your medicines are to:

• Take them at the same time every day.
• Make a note on your calendar each day to show you have taken your medicines.
• Ask someone to remind you to take your medicines every day.
• Keep your medicines in a weekly pill organizer.

Untreated TB disease is often fatal. Even treated, TB disease can cause long-term damage to the lungs, making breathing difficult or causing lung failure.

Untreated pulmonary TB can spread to other organs including your brain, liver, or heart. This could damage these organs, and it is possibly fatal.

TB is curable with treatment, but if left untreated or if not treated fully, it is often fatal. That is why it is very important to follow your doctor’s orders.

People with latent TB will not need to stay away from others.

If you have TB disease, you will need to stay home from school or work and avoid close contact with others. Your doctor will tell you when you are no longer contagious and when you can go back to your regular routine.

You can avoid getting TB by staying away from people who have the disease. Sometimes this is not possible because you may work in a hospital, doctor’s office, nursing facility, prison, or homeless shelter where people have the disease. You may also be caring for a friend or family member who has the disease. To avoid TB in these situations:

• Avoid long periods of time in enclosed rooms with someone who has TB.
• Air out those rooms regularly.
• Cover your face with a mask.

Anyone who is exposed to people who have TB disease should be tested for the disease.