Doctors may overestimate the likelihood that patients will be diagnosed with diseases commonly seen in primary care, a study suggests.

Researchers asked 723 health practitioners in the US to estimate the probability of diagnosis for four scenarios commonly seen in general practice — pneumonia, cardiac ischaemia, breast cancer screening, and urinary tract infections.

The participants, made up of resident doctors, attending doctors and nurse practitioners, were surveyed both before testing and after tests came back with positive or negative results.

A panel of experts had calculated the probability of diagnosis for each scenario, then researchers compared this to the probability of diagnosis provided by practitioners who were presented with each of the scenarios.