Background and aim:

Accurate and prompt diagnosis of acute myocardial infarction (MI) is crucial for improving patient outcomes. Point-of-care high-sensitivity cardiac troponin (POC hs-cTn) assays provide rapid results and aid in decision-making in the emergency department (ED). This study aimed to validate the diagnostic performance of a POC hs-cTnI measurement for early rule-out of non-ST-segment MI (NSTEMI).
Methods and material:

A prospective study was conducted at Slagelse Hospital, Denmark, from October 2022 to January 2023. Eligible participants were ≥18 years with suspected NSTEMI and symptom onset > 3 hours prior to arrival. POC hs-cTnI testing using the Siemens Atellica® VTLi immunoassay was performed alongside standard laboratory hsTnI measurements. A POC hs-cTnI cutoff of < 4 ng/L was considered a rule-out result. The final MI diagnosis was determined by journal audit using the universal definition of MI. Sensitivity, specificity, negative predictive values, and positive predictive values were calculated for POC hs-cTnI.
Results:

Out of 250 screened patients, 64 were included. The prevalence of MI was 9.4% (6 cases). Using a POC hs-cTnI cutoff of < 4 ng/L, three patients were classified as rule-out and 61 as rule-in for acute MI. The rule-out group showed 100% sensitivity and negative predictive value for acute MI. In the rule-in group, specificity and positive predictive value were 5.2% and 9.8%, respectively. No adverse cardiac events or deaths occurred within 30 days among patients with a negative POC hs-cTnI result.
Discussion and Conclusion:

The POC hs-cTnI assay demonstrated its potential for safe NSTEMI rule-out. However, a many false-positive results were observed, leading to potential patient concerns and unnecessary investigations. Incorporating a second POC hs-cTnI test and analyzing troponin trajectories may enhance the ability to safely rule out more patients. Further research is needed to optimize the diagnostic algorithm and improve the clinical utility of the POC hs-cTnI assay.