Evaluation of the use of dried spots and of different storage conditions of plasma for HIV-1 RNA quantification.
OBJECTIVE
The aim of the study was to evaluate the use of dried plasma spots to determine HIV-1 RNA viral loads.


METHODS
The viral loads of 30 liquid plasma samples were compared with those of corresponding dried plasma spots on filter paper (DPS-FP) and in tubes (DPS-T), both of which were left for 7 days at 22 degrees C. Also, 10 liquid plasma samples with detectable viral load were stored at 4, 22 or 37 degrees C for 7 days and five further liquid plasma samples were air-dried for up to 54 h to assess the effects of temperature and the drying step on HIV-1 viral load.


RESULTS
The viral loads of the 30 liquid plasma samples correlated significantly with those of the paired dried spots DPS-FP and DPS-T, but with median losses of 0.64 and 0.69 log(10) HIV-1 RNA copies/mL, respectively, and a limit of detection of 3 log(10) copies/mL. The 10 liquid plasma samples stored for 1 week at 37 degrees C showed a weaker correlation and had a significantly reduced median viral load (-0.92 log(10); P=0.005) when compared with the viral load of the matched plasma stored at - 80 degrees C. Most of the loss happened during the drying step.


CONCLUSIONS
Reliable measurement of HIV-1 RNA viral load requires good plasma storage conditions. HIV RNA stability was affected by desiccation and 1 week of storage at 37 degrees C. However, our findings suggest that liquid plasma can be kept at 4 or 22 degrees C for a week with no effect on viral load.
Amellal
B
B
Laboratoire de Virologie, Hôpital La Pitié Salpêtrière, Paris, France. bahia.amellal@psl.ap-hop-paris.fr
Katlama
C
C
Calvez
V
V
D001793:Blood Preservation; D015925:Cryopreservation; D005260:Female; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D012367:RNA, Viral / Q000097:blood; D012680:Sensitivity and Specificity; D019562:Viral Load
D012367:RNA, Viral