Access Cortisol; DxC 500i Clinical Analyzer

The Access Cortisol assay is a chemiluminescent immunoassay that quantitatively measures cortisol levels in human serum, plasma, and urine to diagnose and treat adrenal gland disorders. The device runs on the DxC 500i Clinical Analyzer, which integrates a chemistry module and an immunoassay module into a single instrument for in vitro diagnostic use.

The candidate device uses the same assay methodology, solid phase (paramagnetic particles), conjugate, substrate, calibrators, and sample types as the predicate Access Cortisol on the Access 2 system. The key difference is that the candidate runs on the DxC 500i integrated platform rather than a standalone Access 2 analyzer, with a measuring range of 2.3–60.0 µg/dL (versus 0.4–60.0 µg/dL for the predicate) and a new reagent IFU (D12398A versus A33262).

CLSI Guideline EP09C-ED3 (method comparison using patient samples), CLSI Guideline EP06-ED2:2020 (linearity evaluation), CLSI Guideline EP05-A3 (precision evaluation), and CLSI Guideline EP17-A2 (detection capability evaluation) were used to establish performance.

Substantial equivalence is supported because the assay chemistry, reagent composition, calibration, and intended use are identical to the predicate, and the analytical processes on both the chemistry and immunoassay modules of the DxC 500i are unchanged from the respective standalone analyzers. Bench testing demonstrates that method comparison slopes meet acceptance criteria (0.974–1.002), linearity holds across the measuring range, precision is within specifications (<12% CV at low concentrations, <10% at higher), and detection limits are clinically appropriate, proving the platform integration does not adversely affect safety or effectiveness.