troponinJournal Club Summary

Methodology Score: 3/5                 
Usefulness Score: 2/5
Shah, AS, et al.
Lancet. 2015 Dec 19;386(10012):2481-8
Editorial:Myocardial infarction: rapid ruling out in the emergency room
Cullen L, et al.
Lancet. 2015 Dec 19;386(10012):2449-50
This prospective cohort study derived and validated a threshold of <5 ng/L at which the negative predictive value of a single high sensitivity troponin value at presentation was greater than 99.5% for ruling out an acute MI, MI at 30 days, or sudden death at 30 days. Although the methods were well done with consecutive enrollment, blinding, and a suitable reference standard, the group was very concerned about the reliance on reporting negative predictive values as the primary outcome, with insufficient data to calculate sensitivity, specificity, or likelihood ratios.
By: Dr. Brandon Ritcey

Epi lesson

Screening Tests in the ED 
Diagnostic tests in the ED are often used to screen many patients for the possibility of severe illness, e.g. ACS in chest pain, SAH in headache, dementia in the elderly. We typically wish to rule-out a condition and such testing must be highly sensitive (SnOut) but will have false positives, e.g Troponin, CT Head, 3DY. In contrast, specialty services may be more interested in ruling in a condition definitively using tests that are highly specific (SpIn), e.g. coronary angiography, CT angiography of the brain, a battery of cognitive tests. 
By: Dr. Ian Stiell