When should PPD tests in healthcare workers be treated?

• A. Any positive result
• B. Only if >15mm of induration
• C. Only if >10mm of induration
• D. Only if symptoms are present

Answer: (C)

The management of positive PPD tests, also known as the tuberculin skin test, in healthcare workers is primarily guided by the size of the induration measured at 48 to 72 hours after the test is administered. A positive result in individuals who are at increased risk, such as healthcare workers, is defined by an induration of >10mm.

This criterion is based on the understanding that healthcare workers may have higher exposure to tuberculosis (TB) and thus a smaller induration measurement can indicate a true positive result, signaling possible recent infection or latent TB infection. The determination to treat based on this threshold is important for prevention, as it helps in identifying individuals who may benefit from preventive therapy to reduce the risk of progression to active TB.

In contrast, other criteria for positive results, such as >15mm of induration, are often used for people who are considered to be at low risk or in general populations, which may not apply to healthcare workers specifically. Therefore, treatment based on >10mm of induration is appropriate to ensure that those who may harbor TB are identified and managed effectively.