Tuberculosis (TB) is an infection that affects the lungs and other parts of the body. It is caused by bacteria (germs). When someone infected with TB coughs, sneezes, speaks, or sings, droplets that contain the bacteria are put into the air. If someone breathes in these droplets, they can get TB.

A skin test for TB helps health care providers know if someone has TB. For the test, the health care provider injected a small amount of fluid (called tuberculin) into the skin on the lower part of your child's arm. A health care provider needs to check the test spot for any swelling in 48–72 hours.

• Return as instructed by your health care provider to have the test spot checked. If you miss the follow-up appointment, your child will have to start the TB test over again.
• Your child can shower or bathe as usual.
• Don't put a bandage, cream, or lotion on the test spot.
• Don't scrub, scratch, or press on the test spot.

Your child:

• Has bleeding, pain, or swelling around the test spot
• Was around someone with TB
• Traveled somewhere where TB is common

Although it is very unlikely, if your child has signs of a serious allergic reaction, such as hives; trouble breathing; and/or swelling of the lips, face, throat, or tongue, call 911 or go to the ER right away.

What do the test results mean? After 48–72 hours, the health care provider measures any swelling at the test spot. Depending on the amount of swelling, the person's risk for TB, and some other considerations, the health care provider decides whether the test is positive or negative.

• A positive test usually means the person is infected with TB. 
• A negative test usually means the person is not infected with TB. 

Someone can also have a positive TB test if they have had TB or the TB vaccine in the past or are sick with an infection. If your health care provider is unsure about what the test results mean, they will order more tests.

What happens if my child has a positive skin test? Kids with a positive TB skin test need other tests. Based on the results of these tests, the health care provider will recommend which treatment is best. Not all people with TB get symptoms, but all people with TB need treatment. Treatment helps the person with TB and also prevents the spread of TB to others.

Who gets TB? Although anyone can get TB, someone has a higher risk of getting TB if:

• They were born in or often travel to a country outside the U.S. where TB is common.
• They live or work where TB is more common in the U.S., such as a homeless shelter, hospital, or jail.