Comparison of the Amplicor HIV-1 monitor test and the nucleic acid sequence-based amplification assay for quantitation of human immunodeficiency virus RNA in plasma, serum, and plasma subjected to freeze-thaw cycles

Abstract

The Amplicor HIV-1 Monitor test was compared to the nucleic acid sequence-based amplification (Nasba) assay system for the quantitation of human immunodeficiency virus (HIV) RNA in three different types of clinical samples: plasma, serum, and plasma subjected to freeze-and-thaw cycles. Each assay detected HIV RNA in the same 73 (90%) of 81 samples tested, and the quantitative results obtained with the two assays were significantly correlated. Both assays detected higher RNA levels in patients with CD4 ؉ cell counts lower than 200 cells/mm 3 than in patients with CD4 ؉ cell counts higher than 200 cells/mm 3. In addition, RNA levels in plasma higher than 5 logs predicted higher numbers of clinical events than did RNA levels in plasma lower than 5 logs. Quantitation of HIV RNA in paired plasma and serum samples showed lower HIV RNA content in serum than in the paired plasma sample, with mean differences between HIV RNA contents of plasma and serum of 0.54 and 0.28 log RNA copy/ml by the Nasba assay and the Amplicor HIV-1 Monitor assay, respectively. No significant loss of HIV RNA was detected with either assay in plasma samples subjected to multiple freeze-and-thaw cycles. These studies demonstrate that the Nasba and Amplicor assays perform similarly with plasma and serum samples. Further, the results indicate that freeze-and-thaw cycles do not result in significant loss of detectable HIV RNA.

Comparison of Levels of Human Immunodeficiency Virus Type 1 RNA in Plasma as Measured by the NucliSens Nucleic Acid Sequence-Based Amplification and Quantiplex Branched-DNA Assays

“…Spearman correlation coefficient analysis indicated that the overall changes in patient viral load patterns were highly correlative between the two assays (P Ͻ 0.001). These results were in agreement with several studies that found that the values obtained by the first-generation nucleic acid sequence-based amplification assay and the Amplicor reverse transcriptase PCR Monitor assay were most often comparable but significantly different from the values obtained with the Quantiplex assay (1,5,7,8,15,19,22,24).…”

“…The NucliSens assay performance characteristics were determined by using HIV-1 RNA standards obtained from the AIDS Clinical Trials Group Virology Laboratories Quality Assurance Program (VQA). The VQA standards were serially diluted to yield the following standards (numbers in parentheses denote the number of times each standard was assayed over several independent test runs): 80 copies/ml (19), 100 copies/ml (20), 500 copies/ml (10), 1,000 copies/ml (8), 1,500 copies/ml (8), 3,000 copies/ml (20), 15,000 copies/ml (8), and 150,000 copies/ml (8). All standards were quantitated with the Nucli-Sens assay according to the manufacturer's instructions.…”

Comparison of NucliSens and Roche Monitor Assays for Quantitation of Levels of Human Immunodeficiency Virus Type 1 RNA in Plasma

“…The linearities of Monitor and Nu-cliSens assay were comparable from approximately 500 to 1,000,000 RNA copies/ml, although Monitor had superior linearity and sensitivity in the lower range and performed variably at RNA levels greater than 1,000,000 copies/ml. These results resemble those found in comparisons of Monitor with the previous generation NASBA assay, which has a lower detection limit of 1,000 RNA copies/ml (3,8). Both assays gave correlation coefficients and linear slopes close to unity when compared with the nominal RNA concentrations present in serially diluted samples.…”

Long‐term stability of human immunodeficiency virus viral load and infectivity in whole blood

“…To evaluate if the drop of 1 log in this fourth patient indicates that viral load is not stable at ¹20 ЊC, further data are needed. In this context, it is interesting to note that up to 3 freeze-thaw cycles at ¹70 ЊC do not significantly influence viral load values [24].…”