Evaluation of the Sentinel-FOB gold faecal immunochemical test for the presence of haemoglobin using the automated Roche Cobas 8000 system

Abstract

ObjectivesFaecal immunochemical tests (FIT) for the detection of haemoglobin are widely used in the diagnostic pathway of colorectal cancer (CRC) in patients presenting with lower abdominal symptoms. Several quantitative immunochemical tests are available, however only a few tests are available on high throughput automated analyzers. Here we report the analytical and clinical evaluation of the Sentinel-FOB Gold assay on the Roche Cobas 8000 automated system. Designand Methods: The assessment of the analytical performance of the assay on the Roche Cobas analyzer comprised determination of imprecision, accuracy, limit of detection, linearity, carryover and prozone effect. In the clinical evaluation part of the study 163 patients presenting for coloscopy with lower abdominal symptoms were included in the study. Diagnostic accuracy and optimal cutoff of the FIT-assay were determined by comparing faecal haemoglobin (f-Hb) concentrations with coloscopy findings as reference. ResultsWe confirmed good analytical performance of the assay on the Roche Cobas system. Patients with CRC had significant higher f-Hb concentrations than patients with non-advanced adenomas and patients with normal findings by coloscopy. When applying a cutoff of 10 μg/g the sensitivity and specificity were 96.2% and 51.8%, respectively for CRC and 84.6% and 57.7% for CRC and advanced adenoma. ConclusionThe Sentinel-FOB Gold assay is appropriate for application on the automated Roche Cobas 8000 analyzer. The assay shows good analytical performance on the system. With regard to early detection of significant colorectal diseases a cutoff of 10 μg/g seems to be optimal.