B-027 CLSI-Based Result Precision on the cobas ISE neo and cobas c 703 Analytical Units Across Two Sites in Europe
Authors: Thorenz A , Findeisen P , Brandt I , Winnock F , Furrer J 
Published: October 2024

Abstract

Background
Novel cobas® pro integrated solutions analytical units, the cobas® ISE neo and cobas c 703 analytical units (all Roche Diagnostics International Ltd, Rotkreuz, Switzerland), were assessed at two sites in Europe (Aalst, Belgium and Heidelberg, Germany). During the system design validation, precision was evaluated under intended use conditions in a routine simulation setting.

Methods
Quality control (QC) materials at two analyte concentrations were measured per site for selected assays (ion selective electrodes [ISEs], general chemistries and specific proteins, and immunochemistry assays); analyte recovery per QC was closely monitored. Precision was evaluated at both study sites based on Clinical and Laboratory Standards Institute EP05-A3 guidelines over 21 days for 53 applications representing the entire assay menu: six ISE serum/plasma and urine applications; 40 clinical chemistry serum/plasma and urine applications (four were measured using cobas c 503 at one site only); and seven immunochemistry serum/plasma applications. Reproducibility under various stressed routine-like conditions, including provocations, was tested using routine simulation imprecision experiments. To test the interaction of new and existing analytical units under routine conditions, two test configurations were used: the first configuration comprised one cobas ISE neo, two cobas c 703, and one cobas e 801 analytical units; and the second configuration comprised one cobas ISE neo, one cobas c 703, one cobas c 503, and one cobas e 801 analytical units. The precision of batch type measurements was compared with the precision under routine simulated random access conditions. Random access coefficients of variance (CVs) that exceeded 1.5× reference batch CVs, or single measurements deviating by &gt;10% from the batch mean, triggered in-depth analysis of the system components that contributed to the result. CVs for intermediate precision comprised measurements from ≤4 cobas c 703 reagent disks, dependent on the system set-up and application assignment. CVs for reproducibility were calculated across four ISE measuring units, ≤3 cobas c 703 reagent disks, or ≤4 cobas e 801 measuring cells.

Results
Using four analytical units, n=511 CVs for repeatability, intermediate precision, and reproducibility were calculated. For repeatability, the median CV for ISE (n=24) was 0.8%, for clinical chemistry (cobas c 703: n=146; cobas c 503: n=8) was 0.9%, and for immunochemistry (n=28) was 1.0%. For intermediate precision, the median CV for ISE (n=24) was 1.1%, for clinical chemistry (cobas c 703: n=146; cobas c 503: n=8) was 1.2%, and for immunochemistry (n=28) was 1.5%. For reproducibility, the median CV for ISE (n=12) was 0.9%, for clinical chemistry (cobas c 703: n=73) was 1.6%, and for immunochemistry (n=14) was 1.7%.

Conclusions
The novel cobas ISE neo and cobas c 703 analytical units demonstrated robust precision, comparable to the existing cobas pro integrated solutions analytical units, over a prolonged period.