When do i get my ppd read

Citation s : Tat D et al. By continuing to use our site, you accept the use of these cookies. To learn more, please visit our Cookie Information page. Medically reviewed by Judith Marcin, M. What happens during a TB skin test? Identifying infection. Images of indurations. Understanding your test results. Symptoms of TB. Next steps after a positive test. Read this next. Medically reviewed by Alana Biggers, M. Medically reviewed by Deborah Weatherspoon, Ph.

Pulmonary Tuberculosis. Medically reviewed by Adithya Cattamanchi, M. Meningeal Tuberculosis. Medically reviewed by Elaine K. Luo, M. What Are Airborne Diseases? The Danger in Delaying or Skipping Vaccinations for Children Some parents have adopted alternative vaccination schedules, but experts say this can pose serious consequences for their children's health.

Types of Tuberculosis. Medically reviewed by Jill Seladi-Schulman, Ph. TB is a highly contagious disease. However, the disease is relatively rare in the United States. You should get a PPD skin test if you work in the healthcare field. All healthcare workers must be routinely screened for TB. A doctor or nurse will swab the skin of your inner forearm with alcohol. You may feel a slight sting.

A bump or small welt will form, which usually goes away in a few hours. The amount of swelling may be different for children, people with HIV, the elderly, and others at high risk. A small reaction, called an induration , at the site of the test 5 to 9 millimeters of firm swelling is a positive result in people who:.

More tests are necessary to confirm the diagnosis. For people without a known risk factor for TB, a 15 mm or larger firm swelling at the injection site indicates a positive reaction. Your doctor will follow up on positive results with a chest X-ray, a CT scan , and a sputum test that looks for active TB in the lungs. Some people infected with the bacteria that cause TB may not have any reaction to the test. Two-step TSTs are not recommended for patients in other settings.

The first "step" may stimulate or boost the immune system's ability to react to the test. If the second "step" is not performed as part of baseline screening, a subsequent positive TST reaction could be misinterpreted as a new infection. BCG is used in many countries with a high prevalence of TB to prevent childhood tuberculous meningitis and miliary disease.

However, BCG is not generally recommended for use in the United States because of the low risk of infection with Mycobacterium tuberculosis , the variable effectiveness of the vaccine against adult pulmonary TB, and the vaccine's potential interference with tuberculin skin test reactivity.