Background: Blood or plasma samples from rural areas are often transported under suboptimal conditions to central laboratories. The negative influence of different storage temperatures during transportation as well as long transportation times on the stability of unprotected HIV RNA is well known. Therefore, the correct and reliable quantification of HIV RNA might be very difficult. A stabilization solution for the storage and transportation of plasma samples was developed which stabilizes RNA for seven days up to 45°C without viral load changes.
Methods: Blood samples from HIV positive individuals were collected into EDTA containing tubes. The isolated plasma samples in Germany were pipetted into pre-prepared RNA stabilization tubes and incubated for seven days at 45°C. HIV-1 RNA quantification was performed on a HIV-1 LCx m 2000 system from Abbott and a Qiagen/Artus HI Virus-1 RG RT-PCR Kit on a Rotor-Gene Q PCR machine. In addition, plasma samples were collected and tested using existing SOP for storage and transportation in Nigeria. Plasma samples were treated with and without stabilization solution and the AMPLICOR HIV-1 MONITORTM test was used to determine viral load.
Results: Seventy-four stabilized plasma samples were tested in Germany and results were compared to those tested unprotected within two hours. No significant changes of viral load were detected up to seven days and 45°C in case of stabilized samples. In contrast RNA of the same unprotected samples was no longer detectable after one day at 45°C. Additionally, 22 plasma samples were investigated on day zero and under field conditions in Nigeria without changes of the viral load after seven days under given temperature conditions.
Conclusions: No cooling chain is necessary for the storage and/or transportation of plasma samples treated with the new RNA stabilization solution for up to seven days. The use of this solution to preserve plasma RNA will be very helpful in countries where the environmental temperature is higher than 30°C, thus addressing the problem of unreliable viral load results due to suboptimal storage or transportation conditions. Further, the costs of storage and transportation of samples for viral load quantification could be significantly reduced.