Real-world analytical and diagnostic evaluation of the Abbott i-STAT Alinity point-of-care high-sensitivity troponin I assay in a UK emergency department

Abstract

Background: High-sensitivity cardiac troponin (hs-cTn) testing is central to emergency department assessment of suspected acute coronary syndrome. Point-of-care hs-cTn testing may reduce turnaround time, but local analytical and clinical evaluation is required before implementation. Methods: In a single-centre real-world evaluation, paired whole-blood and plasma samples from patients with suspected acute coronary syndrome were analysed using the Abbott i-STAT Alinity point-of-care hs-cTnI assay and the Alinity laboratory hs-cTnI assay. Imprecision, method comparison, threshold concordance, diagnostic discrimination for adjudicated Type 1 myocardial infarction (MI), and potential effects of haemolysis, icterus, lipaemia and haematocrit were assessed. Results: Low-level imprecision was below 10% CV. Concordance at the <5 ng/L rule-out threshold was high (84.1%); all discordant classifications reflected higher POCT values, with no false-negative rule-outs. Both assays showed similar discrimination for adjudicated Type 1 MI and 100% observed sensitivity and negative predictive value at the 5 ng/L threshold, although confidence intervals were wide. POCT specificity was lower than laboratory specificity. Method comparison showed a modest positive POCT bias, and regression analyses did not identify clinically meaningful effects of haemolysis, icterus, lipaemia or haematocrit. Conclusion: The Abbott i-STAT Alinity POCT hs-cTnI assay demonstrated analytical performance and clinical concordance supportive of local implementation, with similar diagnostic discrimination to the Alinity laboratory hs-cTnI assay in a small cohort. Larger prospective studies are needed to confirm clinical safety and workflow impact.