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': 'Specificity of a test refers to its ability to detect - \nSelect and explain. \nA. True positive, B. True negatives, C. False negatives, D. False positive', 'role': 'user'}, {'content': 'Answer: B \nExplanation: When a screening test is used to diagnose a disease, the test outcome can be positive (diseased) or negative (healthy), while the actual health status of the person may be different.\nIn that setting\n\n\nTrue positive →\xa0Diseased people correctly diagnosed as diseased.\nFalse positive →\xa0 Healthy people wrongly identified as diseased.\nTrue negative\xa0→ Healthy people correctly identified as healthy.\nFalse negative → Diseased people wrongly identified as healthy.\n\n\nThere are two major statistical measures for the validity of a screening test : -\n\n\nSensitivity\nSpecificity\n\nSensitivity\n\nIt is the ability of a test to identify correctly all those who have the disease, i.e., true positive. \nIn other words sensitivity measures the percentage of sick people who are identified as having disease.\nFor example if a test is 90% sensitive, that means out of 100 diseased people, it will diagnose 90 (90% of diseased people will be diagnosed). Remaining 10% will be wrongly indentified as not having the disease, i.e., false negative.\n\nSpecificity\n\nIt is the ability of a test to identify correctly those who do not have the disease i.e., true negative \nIn other words specificity measures the percentage of well people who are identified as not having the disease.\nFor example, a 90 percent specificity means that 90% of nondiseased people will be identified as not having the disease. The remaining 10% will be wrongly classified as diseased, i.e., false positive.', 'role': 'assistant'}]