Charakterystyka testu cobas® MPX wraz z analizatorem cobas® 6800 oraz aparatem cobas p 680 (Roche) przeznaczonych do automatycznego badania dawców krwi w kierunku RNA wirusa zapalenia wątroby typu C (HCV), RNA ludzkiego wirusa nabytego niedoboru odporności (HIV) i DNA wirusa zapalenia wątroby typu B (HBV)

Background. The cobas MPX test for use with the cobas 6800 System is a qualitative, real-time PCR test for the detection of HIV-1 Groups M and O RNA, HIV-2 RNA, HCV RNA and HBV DNA in human plasma and serum. The test simultaneously identifies HIV, HCV and HBV (multiplex). Optional component to the cobas 6800 System is the cobas p 680 instrument that creates pools from individual samples.Aim. To evaluate the cobas MPX test in individual donations and in plasma pools using the cobas p 680 instrument. Material and methods. Analytical sensitivity was assessed with serial dilutions of the WHO International Standards (IS): HCV, HIV-1, HIV-2, HBV and Performance Panel HIV-1 (O) (Sera Care). Correct identification of reactive donations was evaluated by testing 473 negative and 7 reactive donations in minipools (≤ MP6).Results. Limits of detection (with 95% confidence limits) of cobas MPX were 7.12 IU/mL (4.40–15.62), and 31.33 IU/mL (17.84–76.80) for HCV and HIV-1, respectively. For HBV it was related to dilutions used for Probit analysis and equaled 3.97 IU/mL (2.25–9.75): 1,33 IU/mL (0,89–4,25); 2,05 IU/mL (1.45–3.40). All dilutions of the HIV-1 group O (100–10 copies/mL) and HIV-2 (31.6–10 IU/mL) samples were detected. Results of MPX tests imitating blood screening with the cobas6800 system were in accordance with expected results. Overall, false reactive rates for pooled samples were 0.1%. Conclusions. The cobas MPX test on the cobas 6800 System, including the cobas p 680 instrument demonstrated high sensitivity and satisfactory specificity required in Polish blood donation system. The cobas MPX test correctly identified infected donations without a significant risk of false results.