Important Differences Between Manufacturers When Transitioning From a Contemporary Cardiac Troponin Assay to a High-Sensitivity Cardiac Troponin Assay
Bibliographic record
Abstract
Despite high-sensitivity cardiac troponin (hsTn) assays having superior analytical and clinical performance compared with contemporary cTn assays, there are still analytical issues that may necessitate that clinical laboratories institute additional testing and inform clinicians of errors when reporting hsTn results.1Kavsak P.A. Hill S.A. McQueen M.J. Devereaux P.J. Implications of adjustment of high-sensitivity cardiac troponin T assay.Clin Chem. 2013; 59: 574-576Crossref PubMed Scopus (30) Google Scholar, 2Kavsak P.A. Cerasuolo J.O. Ko D.T. et al.High-sensitivity cardiac troponin i vs a clinical chemistry score for predicting all-cause mortality in an emergency department population.CJC Open. 2020; 20: 296-302Abstract Full Text Full Text PDF Scopus (5) Google Scholar, 3Favresse J. Cadrobbi J. Eucher C. et al.Non-reproducible cardiac troponin results occurring with a particular reagent lot.Clin Chem Lab Med. 2020; 59: e9-e12Crossref PubMed Scopus (4) Google Scholar We have recently identified that the Ortho hsTnI assay misclassifies patients with myocardial injury (∼10% false positives for injury at a hospital and cancer centre), compared with the Abbott hsTnI assay.4Kavsak P.A. Mondoux S. Worster A. et al.Misclassification of myocardial injury by a high-sensitivity cardiac troponin I assay.Can J Cardiol. 2021; 37 (523.e7-8)Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar It is unclear what the impact would be for hospital sites transitioning from a contemporary cTn assay to Ortho’s hsTnI assay and whether the increase in positivity would be evident at another hospital setting. Given this, we assessed the impact of transitioning from a contemporary cTnI assay (Siemens EXL cTnI normal < 0.06 ug/L) to the Ortho hsTnI (female normal: <10 ng/L; male normal: <14 ng/L) using the published 99th-percentile cutoffs on the percentage (%) of positive results at a community hospital with an emergency department (ED) (West Lincoln Memorial Hospital [∼60 beds]). Over the first 18 weeks after commencing Ortho hsTnI testing at this hospital, the % positive was higher (26%; 95% confidence interval [CI]: 25%–29%; n = 1914 total results; 87.0% results from ED in 2020) vs the Siemens cTnI assay in the corresponding timeframe in 2019 (13%; 95% CI: 11%-15%; n = 1628 total results, with 85.6% of results from ED). After the laboratory program instituted duplicate testing for the Ortho hsTnI assay (to mitigate analytical outliers) with any positive results reflexed for Abbott hsTnI, over 4 weeks, the Ortho hsTnI assay still yielded higher % positive results (29%; 95% CI: 24%-34%; n = 452 total results) compared with the Siemens cTnI (21%; 95% CI: 17%-26%; n = 417; total results in 2019; P = 0.02). The Abbott hsTnI assay yielded positivity estimates over these 4 weeks (23%; 95% CI: 19%-28%) similar to those from the Siemens cTnI assay (P = 0.55). The number of patients that were positive by Ortho hsTnI and negative by Abbott hsTnI over these 4 weeks was 15, or 6.4% (95% CI: 3.9%-10.4%) of the population with hsTnI measured. None of these 15 patients had a diagnosis of acute coronary syndrome with the discordant findings between Ortho hsTnI and Abbott hsTnI (Supplemental Table S1). Removal of the Ortho false positives and results with macrocomplexes (Fig. 1) yielded a higher correlation between Ortho hsTnI and Abbott hsTnI in this subgroup (rho = 0.94; 95% CI: 0.91-0.96; n = 91), with closer agreement to what has been observed in patients with symptoms suggestive of acute coronary syndrome.4Kavsak P.A. Mondoux S. Worster A. et al.Misclassification of myocardial injury by a high-sensitivity cardiac troponin I assay.Can J Cardiol. 2021; 37 (523.e7-8)Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar These data support suboptimal performance of Ortho hsTnI for the detection of myocardial injury in the community-hospital setting, with confirmation by another hsTnI assay helpful to prevent a misdiagnosis. We thank the laboratory staff within the Hamilton Regional Laboratory Medicine Program for performing the testing. No funding was received for this letter.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".