First performance verification of automated cobas^® i601 LC-MS/MS in a high-throughput clinical laboratory using...

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the analytical gold standard for measuring many parameters in clinical laboratories but remains labor-intensive, time-consuming, and insufficiently standardized. Automating LC-MS analytics is one way to integrate the advantages of the methodology into laboratory routine. This study aimed to evaluate the performance of the fully automated LC-MS/MS analyzer cobas^® i601 for 25-hydroxyvitamin D (25(OH)D), 5α-dihydrotestosterone (DHT), and 17α-hydroxyprogesterone (17-OHP), and to assess its suitability for routine clinical use.

Analytical performance of the cobas^® i601 was verified for 25(OH)D, DHT, and 17-OHP according to established quality standards by assessing precision, accuracy, linearity, limit of quantitation (LOQ), and measurement uncertainty. Comparability with existing certified or validated routine methods as well as consistency of two chromatographic lines within the instrument were assessed using Passing-Bablok regression and Bland-Altman analysis.

Satisfactory analytical performance was observed for all analytes on both chromatographic lines. Imprecision and bias relative to target values fulfilled the acceptance criteria, with values ≤4.2 % and ≤6.0 %, respectively. Linearity and LOQ claimed by the manufacturer were confirmed. Strong agreement with our conventional LC-MS/MS methods was observed for 25(OH)D and with LC-MS/MS data from external quality assessment schemes for 17-OHP. In contrast, 17-OHP patient sample concentrations were considerably lower and DHT concentrations were slightly lower compared to the radioimmunoassay (DIAsource) and the laboratory-developed LC-MS/MS method we used as references, respectively.

The fully automated cobas^® i601 LC-MS/MS analyzer provides robust analytical performance and its results are both precise and accurate as well as comparable to established LC-MS/MS methods. It enables, for the first time, an efficient high-throughput vitamin D and steroid testing by random-access mass spectrometry in routine clinical laboratories, without having to rely on specially trained personnel.