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Licensed Unlicensed Requires Authentication Published by De Gruyter November 22, 2021

Evaluation of the Atellica TnIH cardiac troponin I assay and assessment of biological equivalence

Carel J. Pretorius ORCID logo, William Parsonage, Louise W. Cullen, Urs Wilgen, Elzahn De Waal, Sandra Klingberg, Goce Dimeski, Rob White, Jaimi Greenslade and Jacobus P.J. Ungerer



We evaluated the analytical performance characteristics and the biological equivalence of the Atellica TnIH assay.


Precision, detection capability, linearity, and sex specific 99th percentiles were determined de novo. Classification of patients relative to the 99th percentiles was used to assess biological equivalence.


Analytical precision and detection capability of the Atellica TnIH assay is excellent with a limit of blank <1 ng/L and 62.5% of women and 93% of men had results above the limit of detection. The 99th percentiles (90% CI) in women were 49 ng/L (31–67) and 70 ng/L (48–121) in men. An asymmetrical distribution involving 5% of results was notable. Agreement was moderate (Kappa 0.58, 95% CI 0.53–0.63) with 20% of patients discordantly classified with Atellica TnIH below and Access hsTnI above the 99th percentiles. Serial results in 195 patients demonstrated good agreement (Kappa 0.84, 95% CI 0.77–0.90). Differences greater than the assay specific reference change values (z≥±1.96) occurred in 65% (95% CI 53–76%) of 99th percentile discordant patients compared to 2.7% (p<0.001) and 76% (p=0.17) of the concordant low and high cTnI groups respectively.


The 99th percentile discordant and the concordantly elevated groups are more alike with respect to their z≥±1.96 rates. This favours an overestimated Atellica TnIH 99th percentile as more likely, and we hypothesize that antibody interference resulting in asymmetric scatter of nearly 5% samples may be the underlying mechanism. Analytical accuracy and interferences in cardiac troponin assays should be investigated and resolved with high priority.

Corresponding author: Carel J. Pretorius, Chemical Pathology, Royal Brisbane and Women’s Hospital Campus, Level 3 Block 7, Herston 4029, QLD, Australia; and Faculty of Medicine, The University of Queensland, Brisbane, Australia, Phone: +617 36460083, E-mail:

Funding source: Siemens Healthineers

  1. Research funding: Reagents were provided at no cost by Siemens Healthineers. The funder played no role in the design, data collection, analysis, drafting or editing and the the decision to submit the manuscript.

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Competing interests: Authors state no conflict of interest.

  4. Informed consent: Not applicable.

  5. Ethical approval: The local Institutional Review Board deemed the study exempt from review (Royal Brisbane and Women’s Hospital Ethical Committee LNR/2021/QRBW/74675).


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Supplementary Material

The online version of this article offers supplementary material (

Received: 2021-09-07
Accepted: 2021-11-12
Published Online: 2021-11-22
Published in Print: 2022-01-27

© 2021 Walter de Gruyter GmbH, Berlin/Boston

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