Viola IL Thulin ,1 Gard Mikael Sæle Myrmel,2 Silje Marie Farestveit Jordalen,1 Ole Christian Lekven ,1,2 Jeyaseelan Krishnapillai,1,2 Ole-Thomas Steiro,2 Richard Body ,3,4 Paul O Collinson ,5 Fred Apple,6 Louise Cullen ,7,8,9 Tone Merete Norekvål,2,10 Torbjørn Wisløff,11,12 Kjell Vikenes ,2,10 Rune Oskar Bjørneklett,1,13 Torbjørn Omland,12,14 Kristin Moberg Aakre
Abstract. 
Introduction While point-of-care (POC) high-sensitivity cardiac troponin (hs-cTn) testing has the potential to reduce emergency department (ED) length of stay (LOS), evidence of real world effectiveness is lacking. Our objective was to examine factors that influence the real world effectiveness of POC hs-cTn-based accelerated diagnostic protocols (ADPs) in reducing ED LOS.
Methods This is a post hoc analysis from the “Aiming towards evidence-based interpretation of cardiac biomarkers in patients presenting with chest pain using POC testing” (WESTCOR-POC) study which included 1494 consecutive patients with suspected acute coronary syndrome presenting to the ED at a moderately sized hospital in Norway. Patients were randomised to receive hs-cTn measurements at admission and after 1 hour either by POC or central laboratory testing. This post hoc analysis examines factors affecting the effectiveness of a POC-based ADP and predictors of non-ADP-concordant disposition. Both outcomes were assessed using regression models, with significance level set at p<0.05.
Results Overall, 36.1% of patients met the ADPs’ early discharge criteria, of which 66% were discharged. In effect-modification analyses, the effect of POC testing on ED LOS differed by concordance with ADP recommendations (interaction p=0.011), with a reduction among patients with ADP-concordant disposition (−14 min 95% CI −26 to −3), but no corresponding reduction among patients with discordant disposition (13.5 min, 95% CI −4.5 to 31.4). Factors predicting hospital admission despite ADP-recommended discharge were: age >60 years (OR 2.3, 95% CI 1.4 to 3.7, p=0.001), high triage category (OR 1.9, 95% CI 1.2 to 3.0, p=0.003) and suspected serious differential diagnosis (OR 5.9, 95% 3.5 to 9.9, p<0.001).
Conclusion Our findings highlight the need for implementation strategies that support ADP concordant disposition decisions and ensure appropriate patient selection to realise the efficiency potential of POC hs-cTn testing in the ED.
