A 58 year old man comes to clinic for evaluation of intermittent hematochezia and a 4 kg unintentional weight loss. Before ordering colonoscopy, investigators studying a fecal immunochemical test note that the pretest probability of colorectal cancer in patients with this presentation is 20%. The team wants to convert this probability into pretest odds before applying a likelihood ratio. Which of the following is the correct pretest odds for disease in this patient population?
- A)0.25GABARITO
- B)4.00
- C)0.20
- D)0.80
- E)1.20
Explicação
Pretest odds are calculated as probability divided by 1 minus probability. With a pretest probability of 0.20, the pretest odds are 0.20/0.80 = 0.25. This conversion is the first step in Bayes based posttest probability calculations. Ver explicação completa e trilha adaptativa →