The effect of storage at different temperatures on the stability of Hepatitis C virus RNA in plasma samples

One important issue related to Hepatitis C virus (HCV) RNA nucleic acid amplification testing (NAT) is the storage conditions of plasma samples in order to obtain reliable results. Many authors have reported that the storage conditions could affect the RNA stability and, hence, HCV RNA detection. We have studied HCV RNA stability in plasma samples after storage at different temperatures (-70, -20, 5 and 25 degrees C). Samples containing different HCV titres were stored and analysed by qualitative or quantitative NAT techniques at defined time points. At -20 degrees C, samples containing high HCV RNA titres were followed-up during approximately 2.6-2.7 years, samples with intermediate concentrations during approximately 1 year and samples with 100 International Units/millilitre (IU/ml) during 2.5 years. Independently of the HCV RNA concentration, the results show absence of decay in HCV RNA detectability. Samples stored at 25 degrees C maintain their HCV RNA titre during 14 days and samples at 5 degrees C were stable for at least 3 months.