Journal Club Summary

Methodology Score: 3/5                 
Usefulness Score: 2.5/5
Geersing GJ, et al. BMJ. 2012 Oct 4;345:e6564.
This was a prospective cohort validation study using the Wells clinical decision rule combined with D-dimer to exclude PE in primary care. The study found in their low risk group (Wells ≤ 4 and neg d-dimer) a false negative rate of (1.5%) (95%CI 0.4-3.74%) and Sn = 94.5% (95%CI 86.6-98.8%) Sp = 51%. Our group agreed the results are likely valid but questioned the utility of this protocol effectiveness at impacting emergency referrals. 
By: Dr. Nathan Hecht
(Presented Dec 2013)

Epi lessonScreening 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