Multi-site Performance Evaluation of the cobas 5800 System and Comparison to the cobas 6800/8800 Systems for Quantitative Measurement of HBV, HCV, and HIV-1 Viral Load

Background The cobas® 5800 System (“cobas 5800”) is a new low to mid-throughput PCR-based nucleic acid testing system which performs both qualitative and quantitative testing, including viral load (VL) determination. cobas 5800 shares numerous design elements and technical characteristics with the existing cobas 6800/8800 Systems. Study Design We compared HBV, HCV, and HIV-1 VL results from cobas 5800 in three different laboratories to those from the same specimens tested on a cobas 6800 system. We also assessed cobas 5800 assay reproducibility by repetitive testing of specimens with VL close to values used as thresholds for patient management or classification. Results The correlation between VL measurements generated using cobas 5800 vs 6800 was extremely high, with r 2 correlation coefficients between 0.990 and 0.999 for the three targets at the different sites. The slope of the Deming regression line ranged from 0.994 (HBV, site 3) to 1.025 (HIV-1, site 1). The standard deviation values ranged from 0.04 to 0.19 log 10 IU/mL for HBV, 0.05 to 0.31 log 10 IU/mL for HCV, and 0.05 to 0.31 log 10 copies/mL for HIV-1. In general, variability was higher at lower VL. Between 98.6% and 100% of results fell within the allowable total difference zone that defines expected variability on the existing 6800/8800 system. Conclusions This multi-site comparison study demonstrates equivalent performance of the new cobas 5800 system compared to cobas 6800. This establishes cobas 5800 as a new option for low to mid-throughout laboratories seeking to optimize efficiency of their viral molecular testing.