A PPD Skin test is a test that checks for tuberculosis. Also known as TB, tuberculosis is a severe infection that often affects the lungs. It is caused by the bacteria Mycobacterium tuberculosis. The bacteria can spread anytime you breathe in air that is exhaled by a person who is infected with TB. It can remain inactive in your body for many years. 

The Five Signs You Need a PPD Test 

TB is extremely contagious, and it is estimated to be second only to HIV and AIDS as the highest global killer, according to the World Health Organization. However, the disease is still quite rare in the United States. Many of the people in the US who have TB do not show symptoms. There are several situations or symptoms you should be aware of that may put you at risk of TB. You may need to have a PPD test if any of the following pertain to you. 

  • You have been around someone who has TB.
  • You have a weakened immune system due to certain diseases like cancer, HIV, or AIDS.
  • If you are taking medications that could weaken the immune system such as steroids
  • You are suddenly experiencing fever, coughing, and night sweats.
  • You have experienced unexplained weight loss.

There are other circumstances where getting a PPD skin test would be necessary, such as if you work in the healthcare industry. All healthcare workers are screened on a routine basis for TB. 

How Is the Tuberculosis Test Performed?

The process of a tuberculosis test is relatively simple. A doctor or a nurse will swab your skin in the inner forearm using alcohol. Then you will receive a small shot that contains PPD underneath the top layer of your skin. It is normal to feel a slight stinging sensation when you receive the shot. A bump or a small welt forms and typically goes away within a few hours. 

After 48 to 72 hours have passed, you will need to return to the office where the test was performed. The healthcare provider will check the area where the shot was administered to see if you had any reactions to the PPD. There is a small risk that you will experience severe redness or swelling on your arm. That is especially true if you have had a positive PPD test in the past. 

Understanding the Results of a PPD Skin Test 

If the area of your skin on your arm where you received the inject is not swollen, or it is only swollen a little after 48 to 72 hours, your test results are negative. A negative result means you likely have not become infected with the bacteria that causes tuberculosis. Keep in mind that the amount of swelling that occurs will vary with people who have HIV, the elderly, children, or others who are at a higher risk. 

A small reaction, known as an induration that is at the site of the test, confirms a positive result in individuals who take steroids, have HIV, have received an organ transplant, or those who have a weakened immune system. It is also a positive result for those who have been in close contact with someone who has TB. 

Larger reactions are a positive result for people who have had a negative PPD skin test within the last two years, are intravenous drug users, are healthcare workers, are immigrants who are from a country that has a high TB rate, or are infants and children who have been exposed to high-risk adults. 

Do You Need More Information About PPD Testing?

Soteria Screening Laboratories has screening options available for all your testing needs, including PPD skin tests. If you have any questions or concerns, you can contact us at any time for more information.

Skip to content