Comparison of the Abbott Alinity m and m2000 assays for the quantification of HIV-1, HCV and HBV in clinical samples

Background: Viral load (VL) determination is an essential parameter of the management of patients infected with HIV, HBV or HCV. Many available molecular systems run on a “batch” mode while “random access” systems provide more flexibility.
Objectives: We compared the performance of HIV-1, HCV and HBV quantification assays on the recently developed Abbott Alinity m system to the m2000 RealTime assays.
Study design: Plasma specimens sent for viral load determination were prospectively tested on m2000 and Alinity m systems, according to manufacturers’ instructions. Additional low and high tittered samples were used to assess reproducibility.
Results: Assays concordance was evaluated from 180 samples for HIV-1, 122 for HBV, and 92 for HCV. A good correlation and a linear relation over the quantification range was observed for the three markers (r > 0.974). The Alinity m assays yielded higher results with a mean quantification bias of 0.22 log cp/ml for 75 HIV-1, 0.3 log IU/ml for 79 HBV, and 0.2 log for 35 HCV samples, though results were equivalent within an allowable difference of 0.3-0.4 log. Qualitative discordance was observed for 43/180 HIV results, 10/122 HBV and 7/92 HCV and involved undetectable or low-level VL.
Conclusion: The Alinity m assays have performance equivalent to m2000. Upon implementation, physicians should be aware of the relative overquantification compared to previous Abbott assays, particularly around clinical decision thresholds. With reduced turnarounds and hands-on times compared to the m2000 system, the Alinity m platform may improve significantly the laboratory workflow efficiency for the benefit of physicians and patients.