In a health care worker who tests positive on a tuberculin skin test after exposure to TB, the most likely interpretation is:

In a health care worker who tests positive on a tuberculin skin test after exposure to TB, the most likely interpretation is:

• A. Active infection requiring immediate treatment
• B. Exposure to another infected person prior to patient contact
• C. Casual contact infection
• D. Dormant infection unlikely to cause symptoms

Answer: (B)

A positive tuberculin skin test indicates TB infection has occurred at some point, but it does not by itself prove that the disease is active. In a health care worker who tests positive after exposure, the most plausible interpretation is that the infection came from exposure to someone with TB before this particular patient contact, i.e., a prior exposure leading to latent TB infection that is now detected by the test. This reflects immune sensitization rather than a new, necessarily active infection from the current exposure. To determine if there is active disease, further evaluation is needed (symptoms, chest X-ray, sputum testing). Casual contact is unlikely to explain a positive test, and latent TB can be asymptomatic but still represent infection rather than a current active illness.

A positive tuberculin skin test indicates TB infection has occurred at some point, but it does not by itself prove that the disease is active. In a health care worker who tests positive after exposure, the most plausible interpretation is that the infection came from exposure to someone with TB before this particular patient contact, i.e., a prior exposure leading to latent TB infection that is now detected by the test. This reflects immune sensitization rather than a new, necessarily active infection from the current exposure. To determine if there is active disease, further evaluation is needed (symptoms, chest X-ray, sputum testing). Casual contact is unlikely to explain a positive test, and latent TB can be asymptomatic but still represent infection rather than a current active illness.