RESUMEN
BACKGROUND: National reference standards are essential to the quality assessment and regulatory approval of in vitro diagnostic medical devices. However, the long-term stability of national reference standards has not been comprehensively secured. This study was performed to assessment on the long-term stability of the hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus-1 (HIV-1) national reference standards intended to be used for the nucleic acid amplification test (NAT). METHODS: The viral loads of the MFDS (Korea Ministry of Food and Drug Safety) working standard and recombinant DNA for HBV, HCV, and HIV-1 were measured before and after storage at −70℃ for up to 72 months using Cobas Ampliprep/Cobas Taqman assays (Roche Molecular System, Inc., Branchburg, USA) at defined time points. RESULTS: The viral loads of national reference standards for in vitro diagnostic medical devices of HBV, HCV, and HIV-1 stored at −70℃ for up to 72 months did not differ significantly from the baseline viral load. The changes in viral load of national reference standards of HBV, HCV, and HIV-1 tested after storage at −70℃ for up to 72 months ranged from −0.36 to 0.16 log10 IU/mL and did not exceed 0.5 log10, which is the estimated intra-assay variation of molecular tests. CONCLUSION: The HBV, HCV, and HIV-1 national reference standards for in vitro diagnostic medical devices intended to be used for the NAT were relatively stable after long-term storage at −70℃ for up to 72 months, regardless of the initial titer.