Direct comparison of clinical decision limits for cardiac troponin T and I. Issue 8 (21st January 2016)

• Record Type: Journal Article
• Authors: Kimenai, Dorien M; Henry, Ronald MA; van der Kallen, Carla JH; Dagnelie, Pieter C; Schram, Miranda T; Stehouwer, Coen DA; van Suijlen, Jeroen DE; Niens, Marijke; Bekers, Otto; Sep, Simone JS; Schaper, Nicolaas C; van Dieijen-Visser, Marja P; Meex, Steven JR
• Is Part Of: Heart. Volume 102:Issue 8(2016)
• Page Start: 610
• Page End: 616
• Publication Date: 2016-01-21
• Subjects: Heart -- Diseases -- Treatment -- Periodicals; Cardiology -- Periodicals; 616.12
• DOI: 10.1136/heartjnl-2015-308917
• Languages: English
• ISSNs: 1355-6037

Abstract

Abstract : Objective: The 99th percentile upper reference limit of high-sensitivity cardiac troponin (hs-cTn) from a healthy reference population is used for diagnosing acute myocardial infarction (AMI). Accepted current thresholds of hs-cTnT (Roche) and hs-cTnI (Abbott) are 14 and 26 ng/L, respectively. Since thresholds for hs-cTnT and hs-cTnI were derived from different reference cohorts it is unclear whether they are biologically equivalent. We directly assessed sex-specific and age-specific 99th percentile upper reference limits of hs-cTnT and hs-cTnI in a single reference cohort, to investigate whether current divergent thresholds of hs-cTnT and hs-cTnI stem from intrinsic assay differences or reflect cohort variation. Methods: A healthy reference population was derived from a population-based cohort (the Maastricht Study: n=3451; age: 40–75 years). Individuals with diabetes mellitus, a history of cardiovascular disease, cardiac ischaemia on ECG, N-terminal pro-brain natriuretic peptide >125 ng/L or estimated glomerular filtration rate <60 mL/min/1.73 m 2 were excluded. Non-parametric analyses were performed to assess 99th percentile upper reference limits. Results: 1540 individuals were included in the healthy reference population (age 57±8 years, 52.4% women). Overall 99th percentile upper reference limits of hs-cTnT and hs-cTnI were 15 and 13 ng/L, respectively. Upper reference limits were higher in men than women (hs-cTnT: 16 vs 12 ng/L), (hs-cTnI: 20 vs 11 ng/L) and increased with age. Conclusions: Direct comparison reveals numerically similar thresholds for hs-cTnT and hs-cTnI assays. This finding is in line with recently reported underdiagnosis of AMI with the current decision limit of 26 ng/L for hs-cTnI, especially among women. Downwards adjustment of the hs-cTnI threshold, differentiated for sex, would equalise clinical decision limits for both assays, and may prevent further underdiagnosis of AMI.