If a Mantoux test is positive in a healthy child with no risk factors, what is the next step?

• A. Ask about exposure to homeless persons
• B. Order a chest radiograph to evaluate for active TB
• C. Reassure that the screen is negative
• D. Refer to an infectious disease specialist

Answer: (B)

A positive tuberculin skin test means TB infection is present, but it does not distinguish between latent infection and active disease. The next step is to obtain a chest radiograph to look for signs of active tuberculosis, because identifying active disease changes immediate management and public health actions. If the chest X-ray is clear, the finding supports latent TB infection and guides subsequent evaluation and treatment; if it shows active disease, appropriate therapy and containment measures must be started. Asking about exposure or reassuring the screen as negative don’t address the need to rule out active TB, and referral to infectious disease isn’t the first step before imaging.