This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening for Disease, Subject name: Social & Preventive Medicine
[{'content': 'Positive predictive value depends on all except - \nSelect and explain. \nA. Sensitivity, B. Specificity, C. Prevalence, D. Incidence', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Incidence o Positive predictive value (PPV) of a screening test depends on : -SensitivitySpecificityPrevalence of diseaseo As the sensitivity and specificity of a test are relatively constant, positive predictive value is mainly dependent on the prevelance of disease.PPV =Sensitivity x Prevalence------------------------(sensitivity x prevalence) + (100-spcificity) (100-prevalence)X100", 'role': 'assistant'}]