B-333 Squamous Cell Carcinoma Antigen Immunoassay Comparability Between Two Commercially Available Analytical Platforms: Abbott Laboratories vs Roche Diagnostics

Background Squamous cell carcinoma (SCC) is an epithelial malignancy most commonly found in the lungs, cervix, head and neck due to the widespread location of epithelial lining in these tissues. Squamous Cell Carcinoma Antigen (SCC-Ag) is used as a marker for prognosis and monitoring of recurrence of squamous cell carcinoma. Our laboratory currently measures SCC-Ag on the Abbott Architect I1000SR system. This study aims to evaluate the analytical performance of the Roche Elecsys SCC-Ag immunoassay and its comparability to the current Abbott Architect SCC-Ag immunoassay, with the final goal of consolidating tumor markers testing onto one single analytical platform. Methods Analytical performance of Roche Elecsys SCC assays was assessed using our laboratory-established technical performance evaluation protocol, which is referenced to CLSI Guidelines. This includes 1) assay imprecision, 2) linearity assessment of analytical measurement range, 3) analytical sensitivity and 4) carry-over study. Method comparison was performed by analysing anonymised patient samples (n=79) on both current Abbott Architect SCC-Ag immunoassay (current) and new Roche Elecsys SCC-Ag immunoassay (new). Statistical analysis was performed using Analyze-It v6.15 software. Results Study results demonstrated that imprecision, linearity, analytical sensitivity and carryover for Roche Elecsys SCC assays are within specifications (within-run and total CVs are <5%, linearity study recoveries of ± 10 %, LOD of 0.20 ng/mL and carryover of <1SD differences, respectively). Method comparison showed a good correlation between Roche Elecsys SCC assay and Abbott Architect SCC assay (Altman-Bland percent difference of +4.85% (95%CI of 3.032-6.668%), Passing Bablok regression equation of [Elecys SCC] = 0.9971 [Architect SCC] + 0.2953, Spearman correlation coefficient, R2 = 0.997). Conclusion The Roche Elecsys SCC assay demonstrated good assay performance specifications and acceptable comparison with the current Abbott Architect SCC assay. This study supports the laboratory’s plan to transit SCC-Ag assay from the Abbott platform to Roche platform, consolidating all tumour markers onto a single platform and more streamlined laboratory work processes.