A screening program for colorectal cancer detects 95% of cases in people with the disease and correctly identifies 90% of people without the disease as disease-free. In the general population, the prevalence of colorectal cancer is 1%. A positive test is obtained in a 60-year-old man. Which of the following best estimates his probability of actually having colorectal cancer?

  1. A)Approximately 9%GABARITO
  2. B)Approximately 95%
  3. C)Approximately 99%
  4. D)Approximately 50%
  5. E)Approximately 85%

Explicação

This is a positive predictive value (PPV) calculation. Sensitivity = 95%, specificity = 90%, prevalence = 1%. Using Bayes' theorem: PPV = (Sensitivity × Prevalence) / [(Sensitivity × Prevalence) + (1 - Specificity) × (1 - Prevalence)] = (0.95 × 0.01) / [(0.95 ... Ver explicação completa e trilha adaptativa →

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