Alternative antibody for the detection of CA125 antigen: a European multicenter study for the evaluation of the analytical and clinical performance of the Access OV Monitor assay on the UniCel DxI 800 Immunoassay System

Background: Cancer antigen CA125 is known as a valuable marker for the management of ovarian cancer. Methods: The analytical and clinical performance of the Access OV Monitor Immunoassay System (Beckman Coulter) was evaluated at five different European sites and compared with a reference system, defined as CA125 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the OV Monitor ranged between 3.1% and 8.8%, and inter-laboratory reproducibility between 4.7% and 5.0%. Linearity upon dilution showed a mean recovery of 100% (SDq8.1%). Endogenous interferents had no influence on OV Monitor levels (mean recoveries: hemoglobin 107%, bilirubin 103%, triglycerides 103%). There was no high-dose hook effect up to 27,193 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access OV Monitor and Elecsys CA125 (Rs0.982, slopes0.921, interceptsq1.951). OV Monitor serum levels were low in healthy individuals (ns267, medians9.7 kU/L, 95th percentiles30.8 kU/L), higher in individuals with various benign diseases (ns549, medianss10.9–16.4 kU/L, 95th percentiless44.2– 355 kU/L) and even higher in individuals suffering from various cancers (ns995, medianss12.4–445 *Corresponding author: Dr. med. Petra Stieber, Institut für Klinische Chemie, Klinikum der Universität München, Marchioninistr. 15, 81366 Munich, Germany Phone: q49-89-7095-3115, Fax: q49-89-7095-6298, E-mail: [email protected] Received July 3, 2007; accepted October 4, 2007 kU/L; 95th percentiless53.4–4664 kU/L). Optimal diagnostic accuracy for cancer detection against the relevant benign control group by the OV Monitor was found for ovarian cancer warea under the curve (AUC) 0.898x. Results for the reference CA125 assay were comparable (AUC 0.899). Conclusions: The Access OV Monitor provides very good methodological characteristics and demonstrates an excellent analytical and clinical correlation with Elecsys CA125. The best diagnostic accuracy for the OV Monitor was found in ovarian cancer. Our results also suggest a clinical value of the OV Monitor in other cancers. Clin Chem Lab Med 2008;46:588–99.