Stability of HIV RNA in plasma specimens stored at different temperatures

In resource-limited countries, HIV-1 RNA quantification is usually performed in reference laboratories. Samples from remote areas are transported under suboptimal conditions. Here we evaluated HIV-1 RNA stability in plasma stored at different temperatures for 1 week.

Blood samples collected in ethylenediaminetetraacetic acid (EDTA) and processed within 6 h of collection were tested by HIV-1 RNA quantification using Roche Cobas Ampliprep-Cobas TaqMan (Roche Diagnostics). The results were compared with matched HIV-1 RNA concentrations determined from plasma stored for 1 week at 4, 22, 30 or 37 degrees C.

A total of 51 samples were evaluated: 10 stored at 4 degrees C, 15 at 22 degrees C, 16 at 30 degrees C and 10 at 37 degrees C. Keeping plasma at 4, 22 or 30 degrees C for 1 week did not affect HIV RNA measurement. Compared with HIV-1 RNA concentrations determined from fresh plasma, the correlation was significant for each of the three temperatures with no RNA decay. In contrast, HIV-1 RNA levels decreased significantly when plasma was stored at 37 degrees C. The 10 samples submitted at this temperature showed a weaker correlation (rho=0.84; P=0.012) and a significantly reduced median HIV-1 RNA concentration (-0.92 log(10) HIV-1 RNA copies/mL; P=0.005).

Plasma can be saved for up to 1 week at 30 degrees C before shipping to a reference laboratory for HIV-1 RNA quantification.