Rowan Health Systems Science (HSS) 1 Practice Test

The main idea is that the treatment threshold is the disease probability at which starting therapy yields more benefit than harm, taking into account how risky the treatment is. If the treatment has substantial risks, side effects, or costs, you need stronger evidence that the patient actually has the disease before you justify treatment. That means the required probability of disease—the threshold—must be higher. In contrast, if the treatment is low risk, the acceptable threshold is lower because the downsides of treating someone who might not need it are smaller. So when a treatment is high risk, the threshold for starting it is high. The option about disease prevalence being zero is not about the threshold itself; with no disease present, there’s no basis to treat, which isn’t the same concept.