>They seem to think that if the prevalence of a disease in the general population (or a specific patient's age/sex/racial demographic) is low, then the probabil

>They seem to think that if the prevalence of a disease in the general population (or a specific patient's age/sex/racial demographic) is low, then the probability of someone presenting with signs and symptoms of the disease having it is also low Because it is also actually low. Signs and symptoms aren't exclusive to specific diseases.