In India, the Mantoux test is performed with 1 TU of PPD RT-23 with Tween 80 injected intradermally. Induration is measured as the transverse diameter at 48 to 72 hours. An induration of how much or more is conventionally read as positive in this country?

• A 5 mm or more
• B 10 mm or more ✓
• C 15 mm or more
• D 20 mm or more

Explanation

Indian convention reads induration of 10 mm or greater as a positive tuberculin test. The 5 mm cutoff applies to HIV-infected or immunosuppressed persons in international practice, and 15 mm is the criterion used in countries where BCG is not universally given and background reactivity is low. Only induration counts; erythema without raised induration is ignored.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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