Researchers examined how many common clinical tests used in one respiratory medicine clinic in the UK were based on high quality evidence (evidence was graded according to a recognised quality scale).
Only half the tests that were used to make or exclude a diagnosis and a fifth of the tests used to assess a known condition were supported by high quality evidence.
This study reflects the practice in a single unit and the proportion of evidence based tests used elsewhere may be higher, stress the authors. Nevertheless, there is a clear need for further high quality research into medical tests, at least in this specialty. There is also a need for an evidence base for the use of trials of therapy.