TY - JOUR
T1 - Discordance between viral loads determined by Roche COBAS AMPLICOR human immunodeficiency virus type 1 monitor (version 1.5) standard and ultrasensitive assays caused by freezing patient plasma in centrifuged Becton-Dickinson vacutainer brand plasma preparation tubes
AU - Salimnia, Hossein
AU - Moore, Ellen C.
AU - Crane, Lawrence R.
AU - MacArthur, Rodger David
AU - Fairfax, Marilynn R.
PY - 2005/9/1
Y1 - 2005/9/1
N2 - The Roche COBAS AMPLICOR human immunodeficiency virus type 1 (HIV-1) Monitor (version 1.5) standard and ultrasensitive viral load assays often gave discordant results, with viral loads from the standard assay exceeding those from the ultrasensitive assay by more than 0.5 log10 for approximately 20% of specimens received. We began studies to determine the extent, magnitude, and reproducibility of the discordance between the assays and to discover and eliminate the cause of this discordance. Until then, we revised our standard operating procedure to include both standard and ultrasensitive testing on all specimens submitted for viral load determinations. Discordant results usually recurred on retesting. They were most prevalent for specimens with ultrasensitive viral loads of <1,000 and rare for specimens with viral loads of >10,000. Often, standard assay results exceeded those of the ultrasensitive assay by 50- to 100-fold. At higher viral loads, the difference between the standard and ultrasensitive assays persisted, but the percent difference was smaller and rarely caused discordance. The proportion of discordant results was significantly higher in specimens from pediatric patients than in specimens from adults. The ultrasensitive viral load determinations generally agreed with the results of the B-DNA (Bayer) viral load assays. If the plasma was transferred from the centrifuged plasma preparation tubes before freezing, standard and ultrasensitive results were concordant with each other and with values determined on plasma from lavender-topped EDTA tubes.
AB - The Roche COBAS AMPLICOR human immunodeficiency virus type 1 (HIV-1) Monitor (version 1.5) standard and ultrasensitive viral load assays often gave discordant results, with viral loads from the standard assay exceeding those from the ultrasensitive assay by more than 0.5 log10 for approximately 20% of specimens received. We began studies to determine the extent, magnitude, and reproducibility of the discordance between the assays and to discover and eliminate the cause of this discordance. Until then, we revised our standard operating procedure to include both standard and ultrasensitive testing on all specimens submitted for viral load determinations. Discordant results usually recurred on retesting. They were most prevalent for specimens with ultrasensitive viral loads of <1,000 and rare for specimens with viral loads of >10,000. Often, standard assay results exceeded those of the ultrasensitive assay by 50- to 100-fold. At higher viral loads, the difference between the standard and ultrasensitive assays persisted, but the percent difference was smaller and rarely caused discordance. The proportion of discordant results was significantly higher in specimens from pediatric patients than in specimens from adults. The ultrasensitive viral load determinations generally agreed with the results of the B-DNA (Bayer) viral load assays. If the plasma was transferred from the centrifuged plasma preparation tubes before freezing, standard and ultrasensitive results were concordant with each other and with values determined on plasma from lavender-topped EDTA tubes.
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U2 - 10.1128/JCM.43.9.4635-4639.2005
DO - 10.1128/JCM.43.9.4635-4639.2005
M3 - Article
C2 - 16145119
AN - SCOPUS:24744446821
SN - 0095-1137
VL - 43
SP - 4635
EP - 4639
JO - Journal of Clinical Microbiology
JF - Journal of Clinical Microbiology
IS - 9
ER -