Suppose that based on symptoms a patient has, his doctor is
60% certain that the patient has a
particular disease. If doctor's suspicions would be
overwhelming, say at least 85%, then he would
recommend a surgery. Under these circumstances, the doctor
opts for quite an invasive and
expensive procedure, which unfortunately is not 100% reliable.
In particular, the test can show
positive even if the patient does not have the disease (false
positive), because of his diabetes.
Chances of this...