Single Troponin Measurement to Rule Out Myocardial Infarction: JACC Review Topic of the Week

Diagnostic performance of Mindray CL1200i high sensitivity cardiac troponin I assay compared to Abbott Alinity cardiac troponin I assay for the diagnosis of type 1 and 2 acute myocardial infarction in females and males: MERITnI study

OBJECTIVES

We examined the 0- and 2-h diagnostic performance of the Mindray high-sensitivity cardiac troponin I (hs-cTnI) assay using two predefined sex-specific 99th percentile upper reference limits (URL) in patients with normal electrocardiograms to aid in the diagnosis of myocardial infarction (MI).

METHODS

Consecutive emergency department patients undergoing serial high-sensitivity cardiac troponin I (hs-cTnI) testing on clinical indication were studied in the 'Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon' (MERITnI) trial (NCT05853042). Plasma hs-cTnI testing was performed using Mindray CL1200i (investigational) and Abbott Alinity (clinical) assays.

RESULTS

In 1,556 patients (60.7 % male, 43.3 % White, 45.8 % Black, 34.8 % chest pain), 2.7 % had type 1 MI, 2.7 % type 2 MI, and 21.5 % non-MI myocardial injury. At 0 h for all MIs (n=86), using package insert URLs and Universal Sample Bank (USB) URLs, sensitivities were 83.7 and 93.0 %. At 0/2 h for all MIs with package insert and USB URLs, sensitivities were higher with serial testing, at 95.3 and 97.7 %. Negative predictive value (NPVs) were excellent and similar for both URLs, ranging from 98 to 100 %. Substantial hs-cTnI concentration differences were observed between sex and injury types. Alinity hs-cTnI diagnostic observations were similar for both package insert and USB URLs.

CONCLUSIONS

The Mindray CL1200i hs-cTnI assay provides the relevant clinical diagnostic information to enable clinicians to deliver cost-effective care for patients to aid in the diagnosis of MI predicated on 0- and 2-h serial testing based on sex-specific 99th percentiles. Novel observations were observed for findings based on different URLs and for females and MI types.

Copeptin in Acute Myocardial Infarction: Is There a Role in the Era of High-Sensitivity Troponins?

The quest for prompt and effective diagnosis of acute myocardial infarction (AMI) has been in the spotlight for decades. Ongoing research focuses on refined biomarker strategies for the early identification and disposition of patients with symptoms suggestive of AMI. Copeptin, a surrogate of the hormone arginine vasopressin, has emerged as a novel biomarker that could potentially aid in the diagnostic approach of patients with chest pain presenting to the emergency department. Observational studies have demonstrated that copeptin is upregulated in patients with AMI, although the exact pathophysiological mechanisms implicated in its release during myocardial ischemia remain unclear. Following these observations, copeptin was proposed as an adjunct to troponin in an effort to augment the diagnostic accuracy of conventional troponin assays. However, after the introduction of high-sensitivity troponin assays, the diagnostic utility of copeptin has been debated. This narrative review aims to elucidate plausible pathophysiological mechanisms involved in copeptin release during myocardial ischemia and to summarize the most recent evidence regarding its diagnostic potential in combination with high-sensitivity troponin assays.

Novel Mindray high sensitivity cardiac troponin I assay for single sample and 0/2-hour rule out of myocardial infarction: MERITnI study

OBJECTIVES

We determined the efficacy of a high sensitivity cardiac troponin I (hs-cTnI) assay for newly derived 0 h and 0/2-h rule-out concentrations for myocardial infarction and determined the safety of incremental changes at low concentrations.

METHODS

Consecutive, emergency department patients undergoing serial hs-cTnI testing on clinical indication were studied in the 'Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon' (MERITnI) trial. Primary safety outcome was the composite of cardiac death and MI at 30 days.

RESULTS

In 1,556 patients (60.7 % male, 43.3 % White, 45.8 % Black. 34.8 % chest pain), 26.9 % patients had at least one hs-cTnI >99th percentile. 2.7 % had type 1 MI, 2.7 % type 2 MI, and 21.5 % non-MI myocardial injury. Single-sample MI rule-out using a normal ECG plus hs-cTnI of <2 ng/L (rounded) ruled out 13.8 % of patients, including early (<2 h) presenters. A 2-h delta of <2 ng/L ruled out an additional 39 % of patients. Based on European Society of Cardiology guidance, derived 0 h<15 ng/L and derived delta of <5 ng/L ruled out 42 % of patients. The Mindray assay showed incremental (non-rounded) analysis discriminated rule out from baseline of <0.1 ng/L at 1.2 % to 2.0 ng/L at 17.0 %. There were no missed adverse outcomes at 30-day assessment for composite of MI and cardiac death.

CONCLUSIONS

The novel Mindray hs-cTnI assay enabled safe and early rule out of MI and cardiac death at very low concentrations in a diverse, cohort utilizing both single sample and 0/2-h rule out protocols, including early presenters.

External validation of the HEART, HEAR, and HET scores for prediction of major adverse cardiac events in adult patients with acute chest pain

BACKGROUND AND IMPORTANCE

In the cohort of patients presenting to the emergency department (ED) with acute chest pain differentiating between those at high risk of major adverse cardiac event (MACE), and those who can safely be discharged, remains a challenge. The history, ECG, age, risk factors, troponin (HEART) score, as well as several abridged versions [history, ECG, age, risk factors (HEAR), history, ECG, troponin (HET)]. are commonly used for this purpose. As with many clinical risk scores, they might be useful, but often lack proper validation. We aimed to externally validate the HEART, HEAR, and HET scores in the setting of a high-volume tertiary care ED in a healthcare system without gatekeeping functions and thus a low-risk population. We further aimed to compare the prognostic performance (discrimination and calibration) of the scores to each other.

DESIGN

External validation study.

SETTINGS AND PARTICIPANTS

On the basis of a-priori sample size calculations, we prospectively included consecutive adult patients presenting to the ED with acute chest pain.

OUTCOME MEASURES AND ANALYSIS

We assessed overall model performance, discrimination, and calibration of all scores, analyzed reclassification from the HEART score and performed decision curve analysis.

MAIN RESULTS

A total of 3273 patients were included, 383 (12%) suffered MACE within 30 days. Classification differed significantly between scores (HEART: 810; 25% low risk; HET: 55; 2%; HEAR: 195; 6%), as did overall performance (area under the curve: 0.85, 0.80, and 0.79, respectively; P < 0.001). HEART score misclassified 7/810 patients (0.9%; 95% confidence interval: 0.4-1.8%) with MACE as low risk, HET 2/55 (3.6%, 0.9-13.8%), and HEAR 0/195, whereas 2087 (72%), 2837 (98%), and 2695 (93%) patients without MACE were erroneously not classified as low risk.

CONCLUSION

The abridged scores fell short of their results in derivation studies, identifying only very few low-risk patients, and showing inferior model performance compared with the original HEART score. Instead of developing new scores, existing scores should be recalibrated to local population characteristics, as needed.

Safety and feasibility of triage and rapid discharge of patients with chest pain from emergency room: A pragmatic, randomized noninferiority control trial of the European Society of Cardiology (ESC) 0 to 1 hour pathway vs conventional 0 to 3 hour accelerated diagnostic protocol

Patients presenting with chest pain represent a significant proportion of Emergency Department (ED) attendances but only a minority, typically 10%, have a final diagnosis of myocardial infarction (MI). Prompt discharge of patients without MI will alleviate ED overcrowding as well as improve patient satisfaction and reduce exposure to risk of hospital acquired infections such as Covid 19. The measurement of cardiac troponin (cTn) by a high sensitivity method is recommended by the National Institute for health and Care Excellence (NICE) for rapid categorization of patients presenting with chest pain. Strategies proposed include measurement on admission and 1 hour from admission (ESC 0-1-hour pathway, the recent guideline approved pathway which has not been implemented widely), and measurement on admission and 3 hours from admission (0-3-hour pathway, which is conventional and widely adopted). The primary objective of this study is twofold: firstly, to assess the safety, feasibility, and impact of implementing the ESC (European Society of Cardiology) 0 to 1-hour pathway in clinical practice by reference to the more established ESC 0 to 3-hour protocol. The principal outcome measure will be the safety of the ESC 0 to 1-hour protocol. However, there are concerns that the time from sample draw to result availability (typically around 60 minutes) will impact on the feasibility of the ESC 0 to 1-hour pathway. Secondly, therefore, our goal is to evaluate whether measurement of high sensitivity troponin by a bedside analyzer (point of care testing, POCT), which will produce results in 15 minutes is a feasible alternative to laboratory testing. We will compare the results produced by POCT with the laboratory results in the context of the ESC 0 to 1 hour and 0 to 3-hour pathway, as a nested controlled study in the context of a randomized controlled trial. (clinicaltrials.gov: NCT05322395).

Clinical impact and predictors of periprocedural myocardial injury among patients undergoing left bundle branch area pacing

BACKGROUND

The clinical impact of Periprocedural myocardial injury (PMI) in patients undergoing permanent pacemaker implantation with Left Bundle Branch Area Pacing (LBBAP) is unknown.

METHODS

130 patients undergoing LBBAP from January 2020 to June 2021 and completing 12 months follow up were enrolled to assess the impact of PMI on composite clinical outcome (CCO) defined as any of the following: all-cause death, hospitalization for heart failure (HHF), hospitalization for acute coronary syndrome (ACS) and ventricular arrhythmias (VAs). High sensitivity Troponin T (HsTnT) was measured up to 24-h after intervention to identify the peak HsTnT values. PMI was defined as increased peak HsTnT values at least > 99th percentile of the upper reference limit (URL: 15 pg/ml) in patients with normal baseline values.

RESULTS

PMI occurred in 72 of 130 patients (55%). ROC analysis yielded a post-procedural peak HsTnT cutoff of fourfold the URL for predicting the CCO (AUC: 0.692; p = 0.023; sensitivity 73% and specificity 71%). Of the enrolled patients, 20% (n = 26) had peak HsTnT > fourfold the URL. Patients with peak HsTnT > fourfold the URL exhibited a higher incidence of the CCO than patients with peak HsTnT ≤ fourfold the URL (31% vs. 10%; p = 0.005), driven by more frequent hospitalizations for ACS (15% vs. 3%; p = 0.010). Multiple (> 2) lead repositions attempts, the use of septography and stylet-driven leads were independent predictors of higher risk of PMI with peak HsTnT > fourfold the URL.

CONCLUSIONS

PMI seems common among patients undergoing LBBAP and may be associated with an increased risk of clinical outcomes in case of more pronounced (peak HsTnT > fourfold the URL) myocardial damage occurring during the procedure.

Analytical validation of the Mindray CL1200i analyzer high sensitivity cardiac troponin I assay: MERITnI study

OBJECTIVES

This study performed an analytical validation study of the Mindray high-sensitivity cardiac troponin I (hs-cTnI) assay addressing limit of blank (LoB), limit of detection (LoD), precision, linearity, analytical specificity and sex-specific 99th percentile upper reference limits.

METHODS

LoB, LoD, precision, linearity and analytical specificity were studied according to Clinical and Laboratory Standards Institute. We used one reagent lot and one CL1200i analyzer. Skeletal troponin I and T, cardiac troponin T, troponin C, actin, tropomyosin, myosin light chain, myoglobin and creatine kinase (CK-MB) were studied for cross-reactivity. Interference with biotin was examined. Lithium heparin samples (one freeze thaw cycle) from healthy males and females were measured to determine the 99th percentiles by using the non-parametric method. Analyses were performed before and after excluding subjects with clinical conditions and/or increased surrogate biomarkers.

RESULTS

The Mindray hs-cTnI assay met criteria to be considered as a hs-cTn assay. LoB and LoD was <0.1 ng/L and 0.1 ng/L, respectively. Repeatability had a coefficient of variation 1.2-3.8 %, and within-laboratory imprecision 1.7-5.0 %. The measuring interval ranged from 1.1 to 28,180 ng/L. The analytical specificity was clinically acceptable for the interferents studied. After exclusions, the 99th percentile URLs obtained were 10 ng/L overall, 5 ng/L for females and 12 ng/L for males.

CONCLUSIONS

Analytical observations of the Mindray hs-cTnI assay demonstrated excellent LoB, LoD, precision, linearity and analytical specificity, that were in alignment with the manufacturer's claims and regulatory guidelines for hs-cTnI. The assay is suitable for clinical investigation for patient-oriented studies.

Early detection of myocardial infarction with reference to baseline levels during health: impact on biological variation of high-sensitivity cardiac troponin

A 78-year-old male was seen in the emergency department (ED) with chest pain. Fifteen months earlier, he had presented to the ED with shoulder and elbow pain. High-sensitivity cardiac troponin I (hs-cTnI) testing was conducted at that time, which produced normal results of 10 and 13 ng/L (cutoff <48 ng/L). During the current admission, his electrocardiogram was unremarkable, with a borderline prolonged PR interval noted. The patient's hs-cTnI results were 25, 47, and 254 ng/L at 0, 1, and 7 hours, respectively. He was diagnosed with demand ischemia and admitted to the hospital. The detection of acute myocardial infarction in this case was made during the first sample collection (t = 0), despite the fact that this result was well within the normal range.

Cardiac Troponin Levels in Patients with Chronic Kidney Disease: "Markers of High Risk or Just Noise''?

Kidney disease is linked to the development of cardiovascular disorders, further increasing morbidity and mortality in this high-risk population. Thus, early detection of myocardial damage is imperative in order to prevent devastating cardiovascular complications within this patient group. Over the years, cardiac biomarkers have been identified and are now widely used in everyday clinical practice. More specifically, available data suggest that cardiac troponin and its regulatory subunits (TnT, TnI, and TnC) reflect the injury and necrosis of myocardial tissue. While cTnC is identical in cardiac and skeletal muscle, TnT and TnI constitute cardiac-specific forms of troponin, and, as such, they have been established by international societies as biomarkers of cardiac damage and diagnostic indicators for acute myocardial infarction. Elevations in the levels of both cardiac troponins (cTnT and cTnI) have been also reported in asymptomatic patients suffering from chronic kidney disease. Therefore, if abnormal, they often generate confusion among clinicians regarding the interpretation and clinical significance of their numerical values in emergency settings. The aim of this review is to explore the reasons behind elevated troponin levels in patients with chronic kidney disease and identify when these elevated levels of biomarkers indicate the need for urgent intervention, considering the high cardiovascular risk in this patient group.

External validation of the preHEART score and comparison with current clinical risk scores for prehospital risk assessment in patients with suspected NSTE-ACS

BACKGROUND

Emergency Medical Services (EMS) studies have shown that prehospital risk stratification and triage decisions in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) can be improved using clinical risk scores with point-of-care (POC) troponin. In current EMS studies, three different clinical risk scores are used in patients suspected of NSTE-ACS: the prehospital History, ECG, Age, Risk and Troponin (preHEART) score, History, ECG, Age, Risk and Troponin (HEART) score and Troponin-only Manchester Acute Coronary Syndromes (T-MACS). The preHEART score lacks external validation and there exists no prospective comparative analysis of the different risk scores within the prehospital setting. The aim of this analysis is to externally validate the preHEART score and compare the diagnostic performance of the these three clinical risk scores and POC-troponin.

METHODS

Prespecified analysis from a prospective, multicentre, cohort study in patients with suspected NSTE-ACS who were transported to an ED between April 2021 and December 2022 in the Netherlands. Risk stratification is performed by EMS personnel using preHEART, HEART, T-MACS and POC-troponin. The primary end point was the hospital diagnosis of NSTE-ACS. The diagnostic performance was expressed as area under the receiver operating characteristic (AUROC), sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV).

RESULTS

A total of 823 patients were included for external validation of the preHEART score, final hospital diagnosis of NSTE-ACS was made in 29% (n=235). The preHEART score classified 27% as low risk, with a sensitivity of 92.8% (95% CI 88.7 to 95.7) and NPV of 92.3% (95% CI 88.3 to 95.1). The preHEART classified 9% of the patients as high risk, with a specificity of 98.5% (95% CI 97.1 to 99.3) and PPV of 87.7% (95% CI 78.3 to 93.4). Data for comparing clinical risk scores and POC-troponin were available in 316 patients. No difference was found between the preHEART score and HEART score (AUROC 0.83 (95% CI 0.78 to 0.87) vs AUROC 0.80 (95% CI 0.74 to 0.85), p=0.19), and both were superior compared with T-MACS (AUROC 0.72 (95% CI 0.66 to 0.79), p≤0.001 and p=0.03, respectively) and POC-troponin measurement alone (AUROC 0.71 (95% CI 0.64 to 0.78), p<0.001 and p=0.01, respectively).

CONCLUSION

On external validation, the preHEART demonstrates good overall diagnostic performance as a prehospital risk stratification tool. Both the preHEART and HEART scores have better overall diagnostic performance compared with T-MACS and sole POC-troponin measurement. These data support the implementation of clinical risk scores in prehospital clinical pathways.

TRIAL REGISTRATION NUMBER

NCT05243485.

Risk scores and coronary artery disease in patients with suspected acute coronary syndrome and intermediate cardiac troponin concentrations

BACKGROUND

Guidelines recommend the use of risk scores to select patients for further investigation after myocardial infarction has been ruled out but their utility to identify those with coronary artery disease is uncertain.

METHODS

In a prospective cohort study, patients with intermediate high-sensitivity cardiac troponin I concentrations (5 ng/L to sex-specific 99th percentile) in whom myocardial infarction was ruled out were enrolled and underwent coronary CT angiography (CCTA) after hospital discharge. History, ECG, Age, Risk factors, Troponin (HEART), Emergency Department Assessment of Chest Pain Score (EDACS), Global Registry of Acute Coronary Event (GRACE), Thrombolysis In Myocardial Infarction (TIMI), Systematic COronary Risk Evaluation 2 and Pooled Cohort Equation risk scores were calculated and the odds ratio (OR) and diagnostic performance for obstructive coronary artery disease were determined using established thresholds.

RESULTS

Of 167 patients enrolled (64±12 years, 28% female), 29.9% (50/167) had obstructive coronary artery disease. The odds of having obstructive disease were increased for all scores with the lowest and highest increase observed for an EDACS score ≥16 (OR 2.2 (1.1-4.6)) and a TIMI risk score ≥1 (OR 12.9 (3.0-56.0)), respectively. The positive predictive value (PPV) was low for all scores but was highest for a GRACE score >88 identifying 39% as high risk with a PPV of 41.9% (30.4-54.2%). The negative predictive value (NPV) varied from 77.3% to 95.2% but was highest for a TIMI score of 0 identifying 26% as low risk with an NPV of 95.2% (87.2-100%).

CONCLUSIONS

In patients with intermediate cardiac troponin concentrations in whom myocardial infarction has been excluded, clinical risk scores can help identify patients with and without coronary artery disease, although the performance of established risk thresholds is suboptimal for utilisation in clinical practice.

TRIAL REGISTRATION NUMBER

NCT04549805.

Dendritic quinary PtRhMoCoFe high-entropy alloy as a robust immunosensing nanoplatform for ultrasensitive detection of biomarker

Recently, high-entropy alloys have superior physicochemical properties as compared to conventional alloys for their glamorous "cocktail effect". Nevertheless, they are scarcely applied to electrochemical immunoassays until now. Herein, uniform PtRhMoCoFe high-entropy alloyed nanodendrites (HEANDs) were synthesized by a wet-chemical co-reduction method, where glucose and oleylamine behaved as the co-reducing agents. Then, a series of characterizations were conducted to illustrate the synergistic effect among multiple metals and fascinating structural characteristics of PtRhMoCoFe HEANDs. The obtained high-entropy alloy was adopted to build a electrochemical label-free biosensor for ultrasensitive bioassay of biomarker cTnI. In the optimized analytical system, the resultant sensor exhibited a dynamic linear range of 0.0001-200 ng mL-1 and a low detection limit of 0.0095 pg mL-1 (S/N = 3). Eventually, this sensing platform was further explored in serum samples with satisfied recovery (102.0 %). This research renders some constructive insights for synthesis of high-entropy alloys and their expanded applications in bioassays and bio-devices.

Uniform or Sex-Specific Cardiac Troponin Thresholds to Rule Out Myocardial Infarction at Presentation

BACKGROUND

Myocardial infarction can be ruled out in patients with a single cardiac troponin measurement. Whether use of a uniform rule-out threshold has resulted in sex differences in care remains unclear.

OBJECTIVES

The purpose of this study was to evaluate implementation of a uniform rule-out threshold in females and males with possible myocardial infarction, and to derive and validate sex-specific thresholds.

METHODS

The implementation of a uniform rule-out threshold (<5 ng/L) with a high-sensitivity cardiac troponin I assay was evaluated in consecutive patients presenting with possible myocardial infarction. The proportion of low-risk patients discharged from the emergency department and incidence of myocardial infarction or cardiac death at 30 days were determined. Sex-specific thresholds were derived and validated, and proportion of female and male patients were stratified as low-risk compared with uniform threshold.

RESULTS

In 16,792 patients (age 58 ± 17 years; 46% female) care was guided using a uniform threshold. This identified more female than male patients as low risk (73% vs 62%), but a similar proportion of low-risk patients were discharged from the emergency department (81% for both) with fewer than 5 (<0.1%) patients having a subsequent myocardial infarction or cardiac death at 30 days. Compared with a uniform threshold of <5 ng/L, use of sex-specific thresholds would increase the proportion of female (61.8% vs 65.9%) and reduce the proportion of male (54.8% vs 47.8%) patients identified as low risk.

CONCLUSIONS

Implementation of a uniform rule-out threshold for myocardial infarction was safe and effective in both sexes. Sex-specific rule-out thresholds should be considered, but their impact on effectiveness and safety may be limited.

Could paramedics use the HEART Pathway to identify patients at low-risk of myocardial infarction in the prehospital setting?

In the Emergency Department, patients with suspected myocardial infarction can be risk stratified using the HEART pathway, which has recently been amended for prehospital use and modified for the incorporation of a high-sensitivity cardiac troponin test. In a prospective analysis, the performance of both HEART pathways in the prehospital setting, with a high-sensitivity cardiac troponin test using 3 different thresholds, was evaluated for major adverse cardiac events at 30 days. We found that both low-risk HEART pathways, when using the most conservative cardiac troponin thresholds, approached but did not reach accepted rule-out performance in the Emergency Department.

Lower Limits for Reporting High-Sensitivity Cardiac Troponin Assays and Impact of Analytical Performance on Patient Misclassification

BACKGROUND

Cardiac troponin measurements are indispensable for the diagnosis of myocardial infarction and provide useful information for long-term risk prediction of cardiovascular disease. Accelerated diagnostic pathways prevent unnecessary hospital admission, but require reporting cardiac troponin concentrations at low concentrations that are sometimes below the limit of quantification. Whether analytical imprecision at these concentrations contributes to misclassification of patients is debated.

CONTENT

The International Federation of Clinical Chemistry Committee on Clinical Application of Cardiac Bio-Markers (IFCC C-CB) provides evidence-based educational statements on analytical and clinical aspects of cardiac biomarkers. This mini-review discusses how the reporting of low concentrations of cardiac troponins impacts on whether or not assays are classified as high-sensitivity and how analytical performance at low concentrations influences the utility of troponins in accelerated diagnostic pathways. Practical suggestions are made for laboratories regarding analytical quality assessment of cardiac troponin results at low cutoffs, with a particular focus on accelerated diagnostic pathways. The review also discusses how future use of cardiac troponins for long-term prediction or management of cardiovascular disease may require improvements in analytical quality.

SUMMARY

Clinical guidelines recommend using cardiac troponin concentrations as low as the limit of detection of the assay to guide patient care. Laboratories, manufacturers, researchers, and external quality assessment providers should extend analytical performance monitoring of cardiac troponin assays to include the concentration ranges applicable in these pathways.

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.