Analytical and clinical performance evaluation of the cobas TaqScreen MPX Test for use on the cobas s 201 system

Clinical specificity, analytical and clinical sensitivities, reproducibility, and subtype/genotype coverage of the cobas TaqScreen MPX Test, a multiplex nucleic acid test with expanded coverage of HIV variants, were determined. A total of 72,281 blood donations were evaluated. The 95% limit of detection (LOD) for the MPX Test inclusive viruses was determined by testing six dilutions of WHO or Roche standards. Over 3000 high-risk and confirmed seropositive specimens were tested with the MPX and COBAS AmpliScreen Tests. Ten subtypes of HIV-1 Group M, HIV-1 Group O, HIV-2 A and B, HBV genotypes A-H, and HCV genotypes 1-6 were tested with the MPX Test. Reproducibility panels were evaluated at three testing sites across three lots. Clinical specificity in pools was 99.99%. There was one HBV yield case. The LODs for HIV-1 Group M, HCV, and HBV were 49, 11, and 3.8 IU/mL, respectively, and 89 and 59.3 copies/mL for HIV-1 Group O and HIV-2, respectively. Concordance between the MPX and the AmpliScreen Tests was 94.9%. Clinical sensitivity based on AmpliScreen comparison was 97.8-99.5%. All genotype/subtype replicates were detected at three times the LOD. Reproducibility was 98.3-100%. In conclusion, the MPX Test is robust and covers HIV-1 Group O and HIV-2.