Effects of anticoagulant, processing delay, and assay method (branched DNA versus reverse transcriptase PCR) on measurement of human immunodeficiency virus type 1 RNA levels in plasma.
We conducted two studies to determine the potential influence of delays in blood processing, type of anticoagulant, and assay method on human immunodeficiency virus type 1 (HIV-1) RNA levels in plasma. The first was an experimental study in which heparin- and EDTA-anticoagulated blood samples were collected from 101 HIV-positive individuals and processed to plasma after delays of 2, 6, and 18 h. HIV-1 RNA levels in each sample were then measured by both branched-DNA (bDNA) and reverse transcriptase PCR (RT-PCR) assays. Compared to samples processed within 2 h, the loss (decay) of HIV-1 RNA in heparinized blood was significant (P < 0.05) but small after 6 h (bDNA assay, -0.12 log(10) copies/ml; RT-PCR, -0.05 log(10) copies/ml) and after 18 h (bDNA assay, -0.27 log(10) copies/ml; RT-PCR, -0.15 log(10) copies/ml). Decay in EDTA-anticoagulated blood was not significant after 6 h (bDNA assay, -0.002 log(10) copies/ml; RT-PCR, -0.02 log(10) copies/ml), but it was after 18 h (bDNA assay, -0.09 log(10) copies/ml; RT-PCR, -0.09 log(10) copies/ml). Only 4% of samples processed after 6 h lost more than 50% (>/=0.3 log(10) copies/ml) of the HIV-1 RNA, regardless of the anticoagulant or the assay that was used. The second study compared HIV-1 RNA levels in samples from the Multicenter AIDS Cohort Study (MACS; samples were collected in heparin-containing tubes in 1985, had a 6-h average processing delay, and were assayed by bDNA assay) and the British Columbia Drug Treatment Program (BCDTP) (collected in EDTA- or acid citrate dextrose-containing tubes in 1996 and 1997, had a 2-h maximum processing delay, and were assayed by RT-PCR). HIV-1 RNA levels in samples from the two cohorts were not significantly different after adjusting for CD4(+)-cell count and converting bDNA assay values to those corresponding to the RT-PCR results. In summary, the decay of HIV-1 RNA measured in heparinized blood after 6 h was small (-0.05 to -0.12 log(10) copies/ml), and the minor impact of this decay on HIV-1 RNA concentrations in archived plasma samples of the MACS was confirmed by the similarity of CD4(+)-cell counts and assay-adjusted HIV-1 RNA concentrations in the MACS and BCDTP.
Department of Epidemiology, Johns Hopkins School of Hygiene and Public Health, Baltimore, Maryland, USA. lkirstei@jhsph.edu
L M
LM
Kirstein
J W
JW
Mellors
C R
CR
Rinaldo
J B
JB
Margolick
J V
JV
Giorgi
J P
JP
Phair
E
E
Dietz
P
P
Gupta
C H
CH
Sherlock
R
R
Hogg
J S
JS
Montaner
A
A
Muñoz
D000163:Acquired Immunodeficiency Syndrome / Q000097:blood / Q000175:diagnosis* / Q000821:virology; D000925:Anticoagulants / Q000494:pharmacology; D004279:DNA, Viral / Q000032:analysis; D054303:HIV Reverse Transcriptase / Q000032:analysis; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D008828:Microbiological Techniques; D016133:Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
D000925:Anticoagulants; D004279:DNA, Viral; D054303:HIV Reverse Transcriptase