ممرضة عمرها ٣٠ سنة تعمل في جناح الصدرية، عُمل لها اختبار السل الجلدي السنوي، والنتيجة ١٢ ملم، وكانت سلبية قبل سنة. أشعة صدرها طبيعية، ولا عندها كحة أو حرارة أو نقص وزن. ماذا يعني هذا؟

A 30-year-old nurse on a respiratory ward has her annual tuberculin skin test: 12 mm induration, negative a year ago. Her chest X-ray is normal and she has no cough, fever or weight loss. What does this mean?

1. Active infectious pulmonary TB needing immediate isolation
2. Latent TB infection needing evaluation and preventive treatment
3. A skin allergy to the injection needing nothing
4. A negative result because the cut-off is 15 mm for everyone

Answer: B) Latent TB infection needing evaluation and preventive treatment. Conversion in a health worker (10 mm or more) with a normal X-ray and no symptoms indicates latent, non-infectious infection. It needs evaluation and usually preventive treatment to stop progression to active TB.