High-Sensitivity Cardiac Troponin Assays: Ready for Prime Time!

Prognostication in emergency room patients: comparing ultrasensitive and contemporary quantification of cardiac troponin levels below the 99th percentile

Introduction

Cardiac troponin levels below the 99th percentile improve the predictive efficacy for cardiovascular events when associated with relevant clinical variables. However, whether ultra-sensitive analytical methods improve this predictive efficacy over less sensitive or contemporary analytical methods remains unknown.

Methods

This retrospective observational study involved consecutive patients who presented to the emergency department for suspected acute coronary syndrome and underwent measurement of ultra-sensitive cardiac troponin I (Singulex) and contemporary cardiac troponin I (Siemens) with levels below the 99th percentile. The clinical characteristics of these patients were analysed, and the efficacy of both analytical methods for predicting cardiovascular events over a 4-year follow-up period was compared.

Results

In total, 838 patients were analysed (mean age, 62.9 ± 16.6 years; 42.2% women). Their cumulative incidence of the composite cardiovascular event (death, readmission for myocardial infarction, and readmission for heart failure) was 25.9% over the 4-year follow-up. Both Singulex cardiac troponin I (analysed by quartiles) and Siemens cardiac troponin (analysed as detectable/undetectable) improved the predictive efficacy for the combined event over clinical variables [Harrell's C-index (95% confidence interval): 0.77 (0.74-0.80) vs. 0.79 (0.76-0.81) and 0.77 (0.74-0.80) vs. 0.78 (0.75-0.81), respectively; p = 0.018]. However, there were no statistically significant difference between the two predictive models that included the aforementioned troponin assays.

Conclusions

Detectable levels of cardiac troponin using a contemporary analytical method or those near the 99th percentile using an ultra-sensitive analytical method improve the predictive efficacy for cardiovascular events, with no differences between the two methods.

Clinical Laboratory Validation Study of a High Sensitivity Troponin I Assay on a POCT (Point of Care Testing) Device

Background

In Acute Coronary Syndrome without ST-segment elevation, the use of high-sensitivity troponins in rapid protocols is considered the gold standard for diagnostic exclusion/confirmation, in conjunction with clinical stratification. The biggest concern regarding the techniques for troponin evaluation is the time required between collection and delivery of the result.

Objective

The objective of the present study is the clinical/laboratory validation of a POCT device for TnI.

Methods

In the first phase of the study, samples from 108 patients with known troponin values High Sensitivity Automated Troponin T (TnT) assay from Roche Diagnostics were analyzed for analytical comparability between hs-cTnI of the Analyzer Atellica® vTLi and hs-cTnT Cobas®. The second phase of the study was performed with samples from 51 patients who reported to the emergency department with chest pain for a clinical prospective evaluation and correlation between the hs-cTnI assays of the Analyzer Atellica® vTLi, hs-cTnT Cobas® and Atellica IM 1300.

Results

There was a correlation between the POCT Atellica® vTLi and hs-cTnT Cobas® in the serum samples of the control group (r = 0.660, p < 0.0001). Besides, there was a correlation between the Atellica® vTLi, serum hs-cTnT Cobas®, plasma hs-cTnT Cobas®, serum Atellica IM and plasma Atellica IM 1300 platforms in the second phase (p < 0.0001 in all cases).

Conclusion

In the present study, the Siemens POCT Atellica® vTLi device showed excellent performance in laboratory validation and correlation with the high-sensitivity TnT assay in different troponin concentration ranges. Given these results, the device can be used in institutions that intend to use a POCT device for 0- and 1-hour chest pain protocols.

Optimizing the Clinical Use of High-Sensitivity Troponin Assays: A Review

Ischemic heart diseases (IHDs) remain a global health concern. Many IHD cases go undiagnosed due to challenges in the initial diagnostic process, particularly in cases of acute myocardial infarction (AMI). High-sensitivity cardiac troponin (hs-cTn) assays have revolutionized myocardial injury assessment, but variations in diagnostic cut-off values and population differences have raised challenges. This review addresses essential laboratory and clinical considerations for hs-cTn assays. Laboratory guidelines discuss the importance of establishing standardized 99th-percentile upper reference limits (URLs) considering factors such as age, sex, health status, and analytical precision. The reference population should exclude individuals with comorbidities like diabetes and renal disease, and rigorous selection is crucial. Some clinical guidelines emphasize the significance of sex-specific URL limits while others do not. They highlight the use of serial troponin assays for AMI diagnosis. In addition, timely reporting of accurate hs-cTn results is essential for effective clinical use. This review aims to provide a clearer understanding among laboratory professionals and clinicians on how to optimize the use of hs-cTn assays in clinical settings in order to ensure accurate AMI diagnosis and thus improve patient care and outcomes.