Q:

What is a two-step PPD test?

A:

Quick Answer

A two-step PPD test involves taking two separate PPD tests at least a week apart, explains The Vaccine Center and Travel Medicine Clinic. Each test requires two doctor visits: one to receive the test injection and another two to three days later to read the test results.

Continue Reading

Full Answer

The Vaccine Center and Travel Medicine Clinic explains that using a two-step PPD process with two separate tests is more likely to give an accurate result than a single test. The PPD, or purified protein derivative, test identifies tuberculosis, explains Healthline. The test involves receiving a small injection of proteins that react to tuberculosis. After two to three days, the doctor examines the injection site. No swelling or minor swelling is a negative result. Interpretation of a positive result depends on both the patient's medical history and the size of the swelling.

Learn more about Diagnostics & Imaging

Related Questions

Explore