Ruling a diagnosis in or out with “SpPIn” and “SnNOut”: a note of caution

Abstract
Dr Y had applied the Ottawa ankle rules—decision rules designed to exclude fractures of the malleolus and the midfoot—and found no bone tenderness.1 He had previously visited the website of a centre for evidence based medicine2 and printed out a list of diagnostic tests that can rule out, or rule in, the condition in question without requiring further investigations.