Background and objectives: This report describes the evaluation of the COBAS AmpliPrep instrument for fully automated generic nucleic acid extraction in conjunction with hepatitis B virus (HBV) DNA, hepatitis C virus (HCV) RNA, and human immunodeficiency virus (HIV)-1 RNA COBAS AmpliScreen amplification and detection using serial dilutions of the WHO international standards (IS) and the PeliCheck reference panels.
Materials and methods: Serial diluted samples of the WHO IS and the PeliCheck reference panels were tested 24 times to determine the HBV DNA, HCV RNA and HIV-1 RNA detection limits by Probit analysis. The existence and extent of cross-contamination were assessed by testing alternating high titre HBV DNA-positive and -negative samples. The specificity of the AmpliPrep-AmpliScreen test for HBV was determined by testing 232 minipools consisting of six donations, all negative for HCV/HIV-1 nucleic acid testing (NAT) and HBsAg. In addition, a HBV genotypes A-G panel was tested.
Results: The respective 95% detection limits (and 95% CI) on the WHO IS and on the PeliCheck reference panels were 6.7 (4.3-13) IU/ml and 123 (68-301) gEq/ml for HBV DNA, 23 (11-106) IU/ml and 126 (84-233) gEq/ml for HCV RNA, and 187 (108-422) IU/ml and 183 (108-434) gEq/ml for HIV-1 RNA. Based on the WHO IS and the PeliCheck reference panels, no significant differences in sensitivity for HBV and HCV were found between AmpliPrep and the licensed MultiPrep extraction method. The sensitivity of AmpliPrep-AmpliScreen for HIV-1 was probably twofold lower as compared to the MultiPrep-AmpliScreen method. No cross contamination was observed. All 232 minipools were HBV NAT-negative. The AmpliPrep-AmpliScreen test for HBV detected HBV genotypes A-G with equal sensitivity.
Conclusions: The AmpliPrep instrument combined with the AmpliScreen assays for HBV, HCV and HIV-1 is robust and suitable for NAT donor screening. The sensitivity criteria for HIV-1 and HCV as defined by the Paul Ehrlich Institute and the Food and Drug Administration for minipool NAT screening are met by this system. SINGLE SENTENCE SUMMARY: Generic COBAS AmpliPrep nucleic acid extraction in conjunction with COBAS AmpliScreen detection for HBV, HCV and HIV-1.