Beyond SpPIN and SnNOUT: Considerations with Dichotomous Tests During Assessment of Diagnostic Accuracy

Paramount to efficient and effective care is the determination of an accurate diagnosis that leads to the proper referral and/or intervention. In an effort to improve the clinical utility of diagnostic accuracy calculations, researchers have promoted the use of the mnemonics SpPIn (if specificity is high, a positive test rules in pathology) and SnNOut (if sensitivity is high, a negative test rules out pathology). Using examples from diagnostic accuracy studies and a review of pertinent literature, this clinimetrics corner outlines additional considerations for clinicians when consuming research in this area. The paper has three foci. First, sensitivity, specificity, and other estimates of the diagnostic accuracy of dichotomous physical examination tests should be viewed as estimates with confidence when those estimates are expressed as confidence intervals. Second, appropriate power must be considered when evaluating each study. Last, the quality of a diagnostic accuracy study can affect the generalizibility of the results to practice environments.