COMPARATIVE STABILITIES OF QUANTITATIVE HUMAN-IMMUNODEFICIENCY-VIRUS RNA IN PLASMA FROM SAMPLES COLLECTED IN VACUTAINER CPT, VACUTAINER PPT, AND STANDARD VACUTAINER TUBES

This study compared the levels of human immunodeficiency virus (HIV) v irion RNA in plasma from whole blood collected in VACUTAINER CPT (cell preparation tube), VACUTAINER PPT (plasma preparation tube), VACUTAIN ER SST (serum separation tube), and standard VACUTAINER tubes with sod ium heparin, acid citrate dextrose, sodium citrate, and potassium EDTA used as anticoagulants. Quantitative plasma HIV RNA levels were measu red by branched-DNA signal amplification, Blood from all tubes was eit her processed within 1 to 3 h after collection or stored at room tempe rature or at 4 degrees C for analysis at 6 to 8 and 30 h postdraw. Imm ediately separated plasma from sodium citrate CPT tubes held at 4 degr ees C maintained better stability of HIV RNA equivalents than whole bl ood held at room temperature or 4 degrees C. The highest number of HIV RNA equivalents was seen with EDTA VACUTAINER tubes. HIV RNA equivale nts in all types of plasma were significantly higher than in SST tubes . Although a decline in HIV RNA equivalents was seen in all collection devices after 30 h, a significantly greater decline in plasma HIV RNA equivalents occurred in acid citrate dextrose VACUTAINER tubes than i n citrate CPT, PPT, and standard EDTA VACUTAINER tubes. In order to mi nimize the variability of quantitative HIV RNA test results, our data suggest that samples collected for a particular assay should be proces sed at the same time postdraw using a particular tube type throughout a given study.