If you’re taking on a new job, a battery of tests and shots are often required. A Purified Protein Derivative Shot, or PPD Shot, is a shot given to test for tuberculosis. Someone infected with tuberculosis (or TB) can show no outward symptoms of infection. It’s for cases like these the PPD shots are useful to diagnose and treat those cases when possible.

Many jobs that will put you in close contact with vulnerable people, like at a nursing home, require this test. Similarly, correctional facilities and homeless shelters also typically require PPD shots before starting to work. All healthcare workers are regularly screened for tuberculosis with a PPD shot test as well. If exposed to tuberculosis, PPD shots reveal whether or not the person’s been infected, even if there are no outward symptoms.

How is a PPD shot taken? When given by a qualified medical professional, PPD shots are as difficult to receive as vaccination or any other shot. What follows is more information on what to expect when receiving the PPD shot.

How the PPD Test is Performed

Taking the PPD test is as easy as receiving any other shot at the doctor’s office. To begin, a doctor or nurse will disinfect the injection site on the inner forearm with alcohol. A small shot containing the PPD test will be injected under the top layer of the skin. As with any injection, there may be a sting and a small bump at the injection site. These symptoms typically go away in a few hours.

After receiving the shot the patient will follow up at the doctor’s office in 48 to 72 hours. The doctor or nurse will check the area to see if there’s been any reaction to the PPD test. There’s a very small risk of severe redness or swelling, especially if receiving the test again after a previous positive. From the reaction, it can be determined whether or not you have a latent TB infection, and plan treatment accordingly.

False positive and false negative results on the PPD test are possible. People who received the Calmette-Guérin vaccine for TB may have a false positive result on the PPD test. In rare cases, people infected with the bacteria that cause TB may not react as well. False negatives also occur if the patient’s immune system is already compromised, such as with cancer or chemotherapy treatments.

What is a PPD Shot?

What is a PPD Shot? A PPD shot is, as its name implies, a shot derived from a purified protein. This protein is one created by the bacterium responsible for tuberculosis (mycobacterium tuberculosis) called tuberculin. This is not the same as the tuberculosis bacterium itself and will not cause infection. However, if your body is already producing tuberculosis antibodies, it will react if it detects the protein’s presence. This is an easy way to show your body has been silently dealing with a TB infection.

The test was originally discovered in 1890 by Robert Koch. Koch was initially hoping for the PPD shot to be a potential treatment or cure for tuberculosis. Later testing proved that PPD shots didn’t work as a treatment or cure for TB. However, the PPD shot remains one of the best ways to diagnose tuberculosis, especially in its inactive state.

Tuberculosis is a highly contagious disease. The World Health Organization (WHO) estimates TB to be second only to HIV/AIDS in terms of global deaths. In the United States, many people infected with TB show no outward symptoms of infection. Those symptoms include things like fever, weight loss, coughing, or night sweats. Most forms of tuberculosis respond to antibiotics, but some forms are also drug-resistant. 

If exposed to TB, especially if you have a compromised immune system, a PPD shot is the best diagnostic choice. For more information about PPD shots and other types of tests and screenings, contact Soteria Screening.