Ruling a diagnosis in or out with "SpPIn
" and "SnNOut": A note of caution.
In many situations, however, the direct handling of LIZ and probabilities may be unfeasible or even risky (26-29), and the gray zone approach may help decision-makers in practice, as do the "SpPIn
" and "SnNOut" rules (1) when they are wisely and critically applied (30).
This is because specific IgE testing is very sensitive and, to recall SnOUT and SpPIN
, a SeNsitive test, when Negative, rules a disease OUT.
I notice that Sackett and Haines continue to use the McMaster mnemonics of "SnNout" (rule out a diagnosis using the high sensitivity of a test) and "SpPin
" (rule in a diagnosis using the high specificity of a test), but I have found, while teaching first-year medical students on two continents, that if the definitions of sensitivity and specificity are clearly understood, there is no need for these mnemonics and the significance and use of the terms of "rule in" and "rule out" are self-evident.