Determination of 19 Cardiac Troponin I and T Assay 99th Percentile Values from a Common Presumably Healthy Population

Abstract

BACKGROUND:Between-assay comparability of 99th percentiles for cardiac troponin concentrations has not been assessed systematically in a single population for a large number of assays.

The 99th percentile of reference population for cTnI and cTnT assay: methodology, pathophysiology and clinical implications

“…Regarding the highly sensitive cTnI assay, results of studies investigating 99th URL values in apparently healthy individuals using the ARCHITECT method are reported in Table 4 [9,14,29,[120][121][122][123][124][125][126]. These data are from a total of 12,768 (11,237 on excluding those reported by manufacturer) apparently healthy subjects of different ethnicities, including Asian [121,123,125], Australian [120], European [14,29,122,126] and North American [9] populations.…”

“…These data are from a total of 12,768 (11,237 on excluding those reported by manufacturer) apparently healthy subjects of different ethnicities, including Asian [121,123,125], Australian [120], European [14,29,122,126] and North American [9] populations. On considering these studies overall [9,14,29,[120][121][122][123][124][125][126], median (25th-75th percentiles), the 99th URL values are 19.3 (13.5-23.7) ng/L (M 26.0 [19.6-29.5] ng/L), and (F 11.9 [10.8-18.3] ng/L). However, these studies vary greatly for population size (range, 366-2608), age of participants (age range 18-98 years), inclusion/exclusion criteria (especially in evaluating presence of asymptomatic cardiac disease and co-morbidities -e.g.…”

“…However, measurement of the 99th URL of cTnI and cTnT levels is a challenging analytical issue due to low biomarker concentrations present in healthy subjects [7][8][9]. Only after 2006 some manufacturers set-up the first new generation of cTnI and cTnT immunoassays with improved analytical sensitivity in accordance with the quality specifications indicated in international guidelines and consensus documents [4,[6][7][8][9][10][11][12][13][14][15][16]. Importantly, highly sensitive methods should also be able to measure troponin levels in the majority of healthy adults subjects (>50%), as suggested in some consensus documents [16][17][18].…”

“…Currently few methods able to completely meet the quality specifications recommended by international guidelines are commercially available for cTn assay [9,[16][17][18]. In one case, for example the manufacturer reports that the limit of blank (LoB) and limit of detection (LoD) for the highly sensitive cTnT method are 2.…”

“…Despite the great improvement achieved in the analytical performance of cTnI immunoassays over the last few years [8], two recent studies demonstrated the persistence of great systematic differences between the results of commercial cTnI methods (on average up to more than 2-fold) [9,23]. The lack of harmonization among the troponin immunoassay methods may generate confusion in physicians, with a consequent misinterpretation of cTnI and cTnT results [8,23,24].…”