Comparative Performance of Cobas 6800, 8800 with Cobas Ampliprep/TaqMan for HIV Viral Load Quantification

Human immunodeficiency virus (HIV) remains a serious public health challenge, especially in Africa. Viral load (VL) is the major marker in monitoring disease prognosis. With the increased demand for HIV VL, countries are equipping fewer laboratories with higher throughput machines based on real-time polymerase chain reaction (PCR) technology. They are fully automated, faster, possess improved assay sensitivity/specificity, higher throughput, more dynamic ranges and reduced contamination rates. This study sought to verify the analytical performance of two new Cobas instruments against the Cobas Ampliprep/TaqMan (CAP/CTM), used in tracking viral suppression in Nigeria. In a cross-sectional study, aliquots of clinical HIV viral load samples were assayed on the three platforms. Values obtained with the CAP/CTM were compared with those from Cobas 6800/8800 in a routine clinical setting. Between June and August 2019, 100 plasma samples collected were analysed in parallel using both techniques. Accuracy, inter-assay precision, linearity and carry-over effect analyses were conducted. The correlation coefficients of 0.997, 0.874, and 0.878 were obtained for C8800/C6800; C8800/CAP/CTM, and C6800/CAP/CTM, respectively. The level of agreement using a Bland–Altman plot was 94.2%. The systems produced good analytical performance, comparable and correlated with CAP/CTM. Therefore, Cobas 6800 and 8800 machines are suitable and acceptable for clinical samples; and recommended for high-volume laboratories.