scholarly journals Discordance with 3 Cardiac Troponin I and T Assays: Implications for the 99th Percentile Cutoff

2016 ◽  
Vol 62 (8) ◽  
pp. 1106-1114 ◽  
Author(s):  
Jacobus Petrus Johannes Ungerer ◽  
Jillian Russyll Tate ◽  
Carel Jacobus Pretorius
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Reference Intervals ◽  
Cardiac Troponin I ◽  
Poor Correlation ◽  
Highly Sensitive ◽  
Analytical Imprecision ◽  
Abbott Architect ◽  
High Sensitive Troponin

Abstract BACKGROUND We compared the 99th percentile reference intervals with 3 modern cardiac troponin assays in a single cohort and tested the hypothesis that the same individuals will be identified as above the cutoff and that differences will be explained by analytical imprecision. METHODS Blood was collected from 2005 apparently healthy blood donors. Cardiac troponin was measured with Abbott Architect STAT high sensitive troponin I, Beckman Coulter Access AccuTnI+3, and Roche Elecsys troponin T highly sensitive assays. RESULTS The 99th percentile cutoff limits were as follows: Abbott cardiac troponin I (cTnI) 28.9 ng/L; Beckman Coulter cTnI 31.3 ng/L; and Roche cardiac troponin T (cTnT) 15.9 ng/L. Correlation among the assays was poor: Abbott cTnI vs Beckman Coulter cTnI, R2 = 0.18; Abbott cTnI vs Roche cTnT, R2 = 0.04; and Beckman Coulter cTnI vs Roche cTnT R2 = 0.01. Of the results above the cutoff 50% to 70% were unique to individual assays, with only 4 out of 20 individuals above the cutoff for all 3 assays. The observed differences among assays were larger than predicted from analytical imprecision. CONCLUSIONS The 99th percentile cutoff values were in agreement with those reported elsewhere. The poor correlation and concordance amongst the assays were notable. The differences found could not be explained by analytical imprecision and indicate the presence of inaccuracy (bias) that is unique to sample and assay combinations. Based on these findings we recommend less emphasis on the cutoff value and greater emphasis on δ values in the diagnosis of myocardial infarction.

scholarly journals Clinical Evaluation of the ACS:180 Cardiac Troponin I Assay

2001 ◽  
Vol 38 (5) ◽  
pp. 509-519 ◽  
Author(s):  
Paul O Collinson ◽  
Nigel Wiggins ◽  
David C Gaze
Keyword(s):  
Endurance Training ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Training Group ◽  
Storage Conditions ◽  
Cardiac Troponin I ◽  
Admission Diagnosis ◽  
Coronary Syndromes ◽  
Analytical Imprecision

All patients admitted to the coronary care unit with suspected acute coronary syndromes were evaluated by serial electrocardiography and blood draws on admission and at 4 and 12h from admission. Diagnosis was based on conventional WHO criteria. Samples were measured for creatine kinase (CK), cardiac troponin T (cTnT), myoglobin, CK isoenzyme MB (CK-MB) and cardiac troponin I (cTnI). A set of samples from individuals undergoing extreme endurance training was also examined. Analytical imprecision was consistent with published quality goals. Samples were stable for cTnI under a range of storage conditions, including multiple freeze-thaw cycles. CK-MB, cTnI and cTnT were equally efficient for the diagnosis of acute myocardial infarction, irrespective of the final diagnostic criteria used. Both cTnI and cTnT were of equal efficiency in the identification of a high-risk subgroup of patients with unstable angina. Significant elevations of cTnI were not seen in an endurance-training group.

scholarly journals Concordance, Variance, and Outliers in 4 Contemporary Cardiac Troponin Assays: Implications for Harmonization

2012 ◽  
Vol 58 (1) ◽  
pp. 274-283 ◽  
Author(s):  
Jacobus P J Ungerer ◽  
Louise Marquart ◽  
Peter K O'Rourke ◽  
Urs Wilgen ◽  
Carel J Pretorius
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Analytical Imprecision ◽  
Universal Definition ◽  
Definition Of ◽  
Abbott Architect ◽  
Roche Cobas

Abstract BACKGROUND Data to standardize and harmonize the differences between cardiac troponin assays are needed to support their universal status in diagnosis of myocardial infarction. We characterized the variation between methods, the comparability of the 99th-percentile cutoff thresholds, and the occurrence of outliers in 4 cardiac troponin assays. METHODS Cardiac troponin was measured in duplicate in 2358 patient samples on 4 platforms: Abbott Architect i2000SR, Beckman Coulter Access2, Roche Cobas e601, and Siemens ADVIA Centaur XP. RESULTS The observed total variances between the 3 cardiac troponin I (cTnI) methods and between the cTnI and cardiac troponin T (cTnT) methods were larger than expected from the analytical imprecision (3.0%–3.7%). The between-method variations of 26% between cTnI assays and 127% between cTnI and cTnT assays were the dominant contributors to total variances. The misclassification of results according to the 99th percentile was 3%–4% between cTnI assays and 15%–17% between cTnI and cTnT. The Roche cTnT assay identified 49% more samples as positive than the Abbott cTnI. Outliers between methods were detected in 1 patient (0.06%) with Abbott, 8 (0.45%) with Beckman Coulter, 10 (0.56%) with Roche, and 3 (0.17%) with Siemens. CONCLUSIONS The universal definition of myocardial infarction should not depend on the choice of analyte or analyzer, and the between- and within-method differences described here need to be considered in the application of cardiac troponin in this respect. The variation between methods that cannot be explained by analytical imprecision and the discordant classification of results according to the respective 99th percentiles should be addressed.

Patterns and Diagnostic Value of Cardiac Troponin I vs. Troponin T and CKMB after OPCAB Surgery*

2001 ◽  
Vol 49 (3) ◽  
pp. 137-143 ◽  
Author(s):  
A. A. Peivandi ◽  
M. Dahm ◽  
U. Hake ◽  
G. Hafner ◽  
U. T. Opfermann ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Diagnostic Value ◽  
Cardiac Troponin I ◽  
Opcab Surgery
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