What is the significance of the PPD test?

The significance of the PPD test, or purified protein derivative test, lies in its role as a screening tool for exposure to tuberculosis (TB). This test is used to determine if a person has been infected with the bacteria that cause TB, even if they do not have active symptoms. When the PPD is administered, a small amount of tuberculin is injected intradermally, and after 48 to 72 hours, the injection site is evaluated for a reaction, which indicates prior exposure to the TB bacteria.

Early detection of TB infection is crucial for preventing the progression to active disease and for controlling its spread within the community. By identifying individuals who have had exposure to TB, healthcare providers can implement appropriate follow-up measures, such as chest X-rays or preventive therapy, further protecting public health.

Other options, such as detecting allergies, measuring blood glucose levels, or assessing liver function, do not pertain to the purpose of the PPD test.