Laboratory diagnostic tests are not perfect and are not 100% accurate
We do not have a test for every disease or virus but most of those pathogens that are of public health importance or have long term implications on your health can be tested
No one single test can be used with absolute certainty to diagnose a disease. Often, we depend on a combination of tests to make a diagnosis
Sometimes, we have to resort to trial treatment or empiric treatment if investigative tests are inconclusive. If the patient makes a therapeutic response and feels better, we have achieved our goal
In PUO, we are looking for treatable causes and to rule out sinister causes eg. malignancies so that we do not miss opportunities for early treatment or intervention