This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Health Programmes in India, Subject name: Social & Preventive Medicine
In RNTCP the most effective tool for case finding is: 
Select and explain. 
A. Sputum examination, B. Radiology, C. Culture, D. Mantoux test
A: Sputum examination
Answer: A: Sputum examination 
Explanation: Ans: A (Sputum examination) Ref: Park 22nd editionExplanation:The case finding tool in RNTCP is Sputum examination.In the previous program NTP there was over reliance on X-ray as the case finding tool.X-ray had low specificity and had lot of difference in opinion in reporting of the X-ray (poor inter rater reliability), hence the case finding tool in RNTCP is sputum examination.In RNTCP, X-ray is used only to diagnose a small proportion of cases such as - sputum negative cases and extra pulmonary tuberculosis such as pleural and pericardial effusion.