The stability of hepatitis C virus RNA after storage at +4 degrees C

One of the major issues in nucleic acid testing is how to store blood samples to obtain reliable results. We therefore studied hepatitis C virus (HCV) RNA concentration in samples after storage at +4 degrees C or freezing and thawing. Six HCV RNA-positive, untreated subjects were studied. Blood samples were collected from these subjects in plasma preparation tubes. The HCV RNA concentration was analysed after storage at +4 degrees C for 168 h or after five freeze-thaw cycles. For HCV RNA quantification we used a qualitative and a quantitative commercial test. After 168 h of storage at +4 degrees C, the HCV RNA concentration was similar to that observed at time-point 0 (5.025 log vs 5.492 log). In one sample we observed a significant fall in HCV RNA concentration. After five freeze-thaw cycles, the HCV RNA concentration was lower than that observed at time-point 0 (4.454 log vs 5.492 log) and in four samples we observed a significant fall in HCV RNA concentration. Our data suggest that HCV RNA is stable in whole blood samples stored at +4 degrees C for 168 h. Based on our results, we conclude that the standard procedures for transport of blood samples (at room temperature for a maximum of 5 h) and storage schedules (+4 degrees C for a maximum of 48 h) can be maintained without compromising the quality of results.