Evaluating Random-Access CLIA for Anti-TNF Drug Monitoring: a Comparison with Traditional ELISA

Accurate therapeutic drug monitoring of anti-TNF biologics such as infliximab and adalimumab and their corresponding antibodies is essential for optimizing treatment in inflammatory conditions. This study aimed to evaluate the analytical and clinical performance of a novel chemiluminescence immunoassay-based system, the i-TRACK10 and compare it to the established LISA Tracker ELISA kits.

A total of 200 clinical serum samples were analyzed for infliximab, adalimumab, and their respective antibodies using both platforms. Positive and negative agreements and precision were calculated using sample sets and controls. Method agreement was assessed via Deming regression, Bland-Altman analysis, and Lin's concordance correlation, following CLSI EP09-A3 guidelines with MedCalc software.

The iTrack10 demonstrated strong association with ELISA across analytes (Pearson's r: 0.91-0.95), but concordance varied (Lin's CCC: 0.75 - 0.93) due to biases. Deming regression slopes (0.58 to 1.52), and Bland-Altman mean biases (-3.52 to 12.58), confirmed proportional differences with moderate variability between methods. Positive and negative agreement values were above 95% across all assays. Precision analysis confirmed low intra- and inter-assay variability, with coefficient of variations generally below 5%. The chemiluminescence immunoassay system offered rapid turnaround, expanded measurement ranges, and random-access operation.

The i-TRACK10 analyzer provides a reliable, accurate, and efficient alternative to traditional ELISA kits for therapeutic drug monitoring of anti-TNF agents. Its enhanced automation and performance characteristics support its integration into routine clinical laboratory workflows.