A fit-for-purpose approach to analytical sensitivity applied to a cardiac troponin assay: time to escape the 'highly-sensitive' trap

作者：Ungerer Jacobus P J^*; Pretorius Carel J

来源：Clinical Chemistry and Laboratory Medicine, 2014, 52(4): 553-556.

DOI：10.1515/cclm-2013-0679

• analytical sensitivity
• limit of detection
• troponin

Background: Highly-sensitive cardiac troponin (cTn) assays are being introduced into the market. In this study we argue that the classification of cTn assays into sensitive and highly-sensitive is flawed and recommend a more appropriate way to characterize analytical sensitivity of cTn assays.
Study: The raw data of 2252 cardiac troponin I (cTnI) tests done in duplicate with a 'sensitive' assay was extracted and used to calculate the cTnI levels in all, including those below the 'limit of detection' (LoD) that were censored. Duplicate results were used to determine analytical imprecision.
Results: We show that cTnI can be quantified in all samples including those with levels below the LoD and that the actual margins of error decrease as concentrations approach zero.
Conclusions: The dichotomous classification of cTn assays into sensitive and highly-sensitive is theoretically flawed and characterizing analytical sensitivity as a continuous variable based on imprecision at 0 and the 99th percentile cut-off would be more appropriate.

• 出版日期2014-4