Imprecision and clinical performance of a whole blood high sensitivity point of care troponin I: the first prospective real-time study in suspected acute coronary syndrome

Abstract

Abstract Introduction Implementation of accelerated diagnostic protocols (ADP) for suspected ACS, with resultant improvement in patient flow, will be facilitated by the use of point of care (POC) testing. To date there has been no published data on the use of a whole blood POC high sensitive troponin (hstn) in real time in a clinical environment. Methods In a nested sub-study of a pragmatic randomised controlled trial consecutive patients with suspected ACS and CP<12 hours duration, underwent sampling for quidell triage true POC hstn I whole blood and plasma (as well as a central laboratory hstn I [Siemens Attellica]. Subjects were randomised to ESC 0/1 and 0/3 hour ADP and had repeat whole blood and plasma POC tn I and laboratory hstn I at these time points. (ClinicalTrials.gov Identifier: NCT05322395). Assay imprecision was assessed by duplicate analysis of whole blood samples at seven levels. Final diagnosis was adjudicated based on all relevant clinical and imaging data together with hstn T as the diagnostic biomarker in clinical use. (Roche diagnostics, 10% coefficient of variation (CV) 3-5 ng/L, 99th percentile 14 ng/L) using the 4th universal definition of myocardial infarction (MI) Results 1157 patients consented and had both investigational POC whole blood and plasma (taken and analysed in real time) and central lab hstn I available. The mean age was 58, 48% were female and 15.4% patients had suffered a previous MI. Assay imprecision of whole blood POC quidel triage true revealed 10% CV at 8.6 ng/L, (>50% lower level than 99th percentile [20.4ng/l]) and a 20% CV at 1.2 ng/l). There was excellent overall agreement between laboratory hsTnI method and whole blood poc cTnI [Quidell triage true = 1.28cTnI Attelica +1.3]. ROC (receiver operator characteristics) curves were computed for each assay against adjudicated index MI to study clinical performance. At all time points there were excellent performance for whole blood POC: AUC 0.97 [95% CI 0.94-098]), 0.98 [95% CI 0.97-1.00] and 0.95 [95% CI0.92-0.98] at time 0 (presentation, figure), 1 and 3 hours respectively. There was statistical equivalence for performance of whole blood POC and plasma POC hstn I and laboratory hstn I Conclusion The POC whole blood quidell triage true demonstrates imprecision levels consistent with high sensitivity characteristics and has a clinical performance equivalent to an established and well validated laboratory hstn I. This is the first clinical validation of Whole blood POC hstn assay studied real-time in a clinical environment.