A client has a tuberculin skin test showing a 7 mm induration. Which statement best describes this result?

• A. The result indicates you are infected with the TB organism.
• B. The test rules out TB infection.
• C. The test confirms active TB disease.
• D. The test shows you are immune to TB.

Answer: (A)

A tuberculin skin test shows exposure to the TB bacteria by producing a delayed-type hypersensitivity reaction. A 7 mm induration is interpreted as positive in people with certain risk factors (such as recent TB contact, HIV, or other immunocompromising conditions), which means there has likely been infection with the TB organism at some point. This indicates infection, but it does not prove active disease and it does not imply immunity. If the test is positive, further evaluation—like a chest X-ray and possibly sputum testing or an IGRA—helps determine whether the infection is latent or active. The other statements don’t fit because a positive test does not rule out infection, does not confirm active TB, and does not indicate immunity.