This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'The purpose of screening test? \nSelect and explain. \nA. To diagnose the cases, B. To so out persons who are at increased risk, C. To segregate diseased and non-diseased persons, D. None', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., To so out persons who are at increased risk o The basic purpose of screening is to so out from a large group of apparently healthy persons those likely to have disease or at increased risk of disease under study, to bring those who are apparently abnormal under medical supervision and treatment. o Screening test is carried out in the hope that earlier diagnosis and subsequent treatment ourably alters the natural history of the disease in a significant propoion of those who are identified as 'positive'.", 'role': 'assistant'}]