What is the correlation between point-of-care high sensitivity troponin I (hs-TnI) and standard laboratory high sensitivity troponin I (hs-TnI)?

From the Guidelines

Point-of-care high sensitivity troponin I (POC hs-TnI) tests generally show good correlation with standard laboratory high sensitivity troponin I assays, with the most recent evidence suggesting that high-sensitivity assays provide higher diagnostic accuracy 1. The correlation between point-of-care high sensitivity troponin I (hs-TnI) and standard laboratory high sensitivity troponin I (hs-TnI) is crucial for diagnosing acute coronary syndromes.

• The clinical implications of the difference in sensitivity between POC tests and central laboratory platforms are most relevant in early presenters or in detecting minor myocardial injury.
• When implementing POC testing, it's essential to establish institution-specific protocols that account for these differences, including appropriate cutoff values which may differ from laboratory-based assays.
• The main advantage of POC testing is the significantly reduced turnaround time, which can expedite clinical decision-making in emergency settings, potentially reducing emergency department length of stay and improving patient flow.
• According to the 2020 ESC guidelines, high-sensitivity assays are recommended over less sensitive ones, as they provide higher diagnostic accuracy at identical low cost 1.
• The majority of currently used point-of-care tests (POCTs) cannot be considered sensitive or high-sensitivity assays, and therefore, the conditions presenting with chest pain, such as aortic dissection and pulmonary embolism, may also result in elevated cardiac troponin concentrations and should be considered as differential diagnoses 1.
• Elevations beyond 5-fold the upper reference limit have high (>90%) positive predictive value for acute type 1 MI, while elevations up to 3-fold the upper reference limit have only limited (50-60%) positive predictive value for AMI and may be associated with a broad spectrum of conditions 1.
• Rising and/or falling cardiac troponin levels differentiate acute (as in MI) from chronic cardiomyocyte damage (the more pronounced the change, the higher the likelihood of AMI) 1.

From the Research

Correlation Between Point-of-Care and Standard Laboratory High Sensitivity Troponin I (hs-TnI)

• The correlation between point-of-care high sensitivity troponin I (hs-TnI) and standard laboratory high sensitivity troponin I (hs-TnI) has been evaluated in several studies 2, 3, 4, 5.
• A study published in 2024 found that the point-of-care hs-TnI assay exhibited equivalent sensitivity and negative predictive values to the laboratory assay, but outperformed the laboratory assay in terms of specificity and positive predictive value 2.
• Another study published in 2019 developed a diagnostic algorithm for a high-sensitivity troponin I point-of-care assay and found that its diagnostic performance was highly comparable to a laboratory-based high-sensitivity troponin assay 3.
• A study published in 2014 compared a new point-of-care troponin assay with a high sensitivity assay and found that the new point-of-care assay had improved sensitivity for acute myocardial infarction (AMI) and major adverse cardiac events (MACE) compared to its predecessor, and comparable sensitivity to a high sensitivity assay 4.
• A study published in 2022 found that a point-of-care hs-TnI assay was statistically equal to a high sensitivity laboratory assay in terms of diagnostic accuracy for AMI or MACE in patients with suspected myocardial infarction 5.
• The implementation of high-sensitivity and point-of-care cardiac troponin assays into practice has been discussed in a review published in 2021, which highlighted the importance of providing point-of-care high-sensitivity cardiac troponin assays and optimizing studies to allow clearance of these assays by regulatory agencies 6.

Diagnostic Performance

• The diagnostic performance of point-of-care hs-TnI assays has been found to be highly comparable to laboratory-based high-sensitivity troponin assays 3, 4, 5.
• The sensitivity, specificity, and negative predictive value of point-of-care hs-TnI assays have been reported to be high, with values ranging from 91.76% to 100% 2, 3, 4, 5.
• The use of point-of-care hs-TnI assays has been found to be safe and effective in clinical practice, with the potential to reduce turnaround time and length of stay in emergency departments 3, 5.

Clinical Application

• The clinical application of point-of-care hs-TnI assays has been found to be useful in the diagnosis of AMI and MACE 2, 3, 4, 5.
• The use of point-of-care hs-TnI assays has been found to be acceptable for the identification of AMI and prediction of MACE in the emergency department environment 5.
• The implementation of high-sensitivity and point-of-care cardiac troponin assays into practice has the potential to improve patient management and outcomes 6.