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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma human immunodeficiency virus RNA in 491 clinical specimens was measured by LCx. There was a strong correlation with the results provided by other methods (r(2) values of 0.93 with Cobas-Monitor version 1.5 and of 0.95 with Quantiplex version 3.0). However, values were uniformly higher with LCx than with Quantiplex when non-B subtypes were tested.
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PMID:Evaluation of the Abbott LCx quantitative assay for measurement of human immunodeficiency virus RNA in plasma. 1192 86

The effect of the addition of a coprecipitant during the RNA isolation step on the analytical performance of the COBAS AMPLICOR human immunodeficiency virus type 1 (HIV-1) Monitor (version 1.5; Roche) viral load test was tested. Thirty-six specimens including patient samples, positive control samples, and negative control samples were processed in the presence and absence of the Pellet Paint coprecipitant. Specimens processed without the coprecipitant had lower RNA yields, as evidenced by a lower signal for the quantitation standard (QS). In addition, the results for all samples processed with the coprecipitant were acceptable on the basis of the optical density (OD) reading for the QS, whereas the result for one specimen processed without the coprecipitant was unacceptable on the basis of the OD reading for the QS, which required the assay to be repeated. Furthermore, the use of the coprecipitant improved the overall precision of the assay.
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PMID:Improvement of AMPLICOR human immunodeficiency virus type 1 viral load test (version 1.5) by addition of a coprecipitant during the RNA isolation step. 1208 88

The analytical performance of the NucliSens HIV-1 QT assay, a highly sensitive test based on nucleic acid sequence-based amplification technology, was evaluated in a multicenter trial. Assay specificity was evaluated with 502 plasma (EDTA) specimens from human immunodeficiency virus type 1 (HIV-1)-seronegative volunteer donors. No HIV-1 RNA was reported in any of the donor specimens. Analytical sensitivity and reproducibility were estimated with panels prepared from a high-titer well-characterized HIV-1 RNA stock (5.84 x 10(8) RNA copies/ml). The assay's dynamic range was linear from 10(6) to 10(1) HIV-1 RNA copies, with a lower detectable limit of 25 copies/ml and a 95% detection rate of 176 copies/ml. Sensitivity of the assay to detect HIV-1 RNA in clinical specimens from patients (n = 101) and in commercially available or prepared panels (n = 24) was compared with NASBA HIV-1 RNA QT (an earlier version of NucliSens HIV-1 QT) and with the Food and Drug Administration-approved standard and ultrasensitive AMPLICOR HIV-1 MONITOR, version 1.0, assays. Detection of HIV-1 RNA was reproducible over a 5-log range (mean standard deviation = 0.15 log). The NucliSens and the standard AMPLICOR assays were equivalent in detection of HIV-1 RNA (concentration, 10(3) to 10(5) copies/ml) in 57 clinical specimens. The NucliSens assay was more sensitive in detecting HIV-1 RNA at lower concentrations (</=10(2) copies/ml) (44 of 44) than either the standard AMPLICOR test (12 of 19) or the NASBA assay (10 of 25). A 25% increase in HIV-1 RNA detection frequency with panels was observed with the NucliSens assay (23 of 24) compared with the standard AMPLICOR test (17 of 24). The new assay was highly specific and demonstrated good sensitivity with a broad linear dynamic range.
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PMID:Multicenter evaluation of the performance characteristics of the NucliSens HIV-1 QT assay used for quantitation of human immunodeficiency virus type 1 RNA. 1251 43

We developed and verified an automated sample processing protocol for use with the AMPLICOR HIV-1 MONITOR test, version 1.5 (Roche Diagnostics, Indianapolis, Ind.). The automated method uses the MagNA Pure LC instrument and total nucleic acid reagents (Roche Applied Science, Indianapolis, Ind.) to extract human immunodeficiency virus type 1 (HIV-1) RNA from plasma specimens. We compared the HIV-1 load results for a dilution series (1 to 5 nominal log(10) copies/ml) and 175 clinical specimens processed by the automated method to those for the same samples processed by the manual methods specified by the manufacturer. The sensitivity, dynamic range, and precision of the viral load assay obtained by automated processing of specimens were similar to those obtained by an ultrasensitive manual processing method. The results were highly correlated (R(2), 0.95), and were in close agreement, with a mean difference of 0.09 log(10) (standard deviation, 0.292). The limits of agreement were +/-0.58 log(10) for results for samples processed by both the manual and the automated methods. These performance characteristics were achieved with a smaller sample volume (200 versus 500 microl) and without a high-speed centrifugation step and required only 15 min of labor for a batch of 32 samples. In conclusion, the automated sample preparation protocol can replace both the standard and the ultrasensitive manual methods used with the AMPLICOR HIV-1 MONITOR test and can substantially reduce the labor associated with this test.
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PMID:Development and verification of an automated sample processing protocol for quantitation of human immunodeficiency virus type 1 RNA in plasma. 1273 49

Dried blood spots (DBS) on filter paper facilitate the collection, transport, and storage of blood samples for laboratory use. A rapid and simple DNA extraction procedure from DBS was developed and evaluated for the diagnosis of human immunodeficiency virus type 1 (HIV-1) infection in children by an in-house nested-PCR assay on three genome regions and by the Amplicor HIV-1 DNA prototype assay version 1.5 (Roche Molecular Systems). A total of 150 samples from children born to HIV-1-infected mothers were collected in Kigali, Rwanda, in parallel as DBS and as peripheral blood mononuclear cell (PBMC) pellets. The results obtained on DBS by the two PCR assays were compared to the results of nested PCR on PBMCs. Of 150 PBMC samples, 10 were positive, 117 were negative, and 23 were indeterminate for HIV-1 infection. In DNA extracted from filter papers and amplified by using the in-house nested PCR, 9 of these 10 positive samples (90%) were found to be positive, and 1 was found to be indeterminate (only the pol region could be amplified). All of the negative samples and all of the 23 indeterminate samples tested negative for HIV-1 infection. When we used the Amplicor DNA test on DBS, all of the 10 PBMC-positive samples were found to be positive and all of the 23 indeterminate samples were found to be negative. Of the PBMC-negative samples, 115 were found to be negative and 2 were found to be indeterminate. We conclude that this simple rapid DNA extraction method on DBS in combination with both detection methods gave a reliable molecular diagnosis of HIV-1 infection in children born to HIV-infected mothers.
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PMID:Simple DNA extraction method for dried blood spots and comparison of two PCR assays for diagnosis of vertical human immunodeficiency virus type 1 transmission in Rwanda. 1471 26

The agreement of the microwell plate AMPLICOR HIV-1 MONITOR version 1.0 (MWP 1.0), the microwell plate AMPLICOR HIV-1 MONITOR version 1.5 (MWP 1.5), and the COBAS AMPLICOR HIV-1 MONITOR version 1.5 (COBAS 1.5) tests was evaluated using clinical specimens and well-characterized control material. Two hundred patient plasma specimens and a panel of known human immunodeficiency virus type 1 (HIV-1) subtypes were tested. All data were log(10) transformed prior to analysis. The 95% limits of agreement for the three tests at the average of 3.66 log(10) copies/ml were +/- 0.28 log(10), +/- 0.34 log(10), and +/- 0.34 log(10) copies/ml for MWP 1.0-MWP 1.5, MWP 1.0-COBAS 1.5, and MWP 1.5-COBAS 1.5, respectively. Ten specimens (6.1%) had differences exceeding the limits of agreement for the MWP 1.0 and MWP 1.5 tests. Correlation coefficients among the three tests were high (r >or=0.96). The viral-load values obtained with the MWP 1.0 test were only 2.1% higher on average than those measured with the MWP 1.5 test and 1.6% higher than those seen with the COBAS 1.5 test. The MWP 1.5 test values were 0.8% higher than the COBAS 1.5 test values. Overall, there was less agreement among the different tests for viral-load values near the lower limit of quantification. The MWP 1.0 test underquantified subtypes A, E, F, G, and H by 1.0 to 2.0 log(10) copies/ml; this problem was not observed with the MWP 1.5 test. The close agreement among the results obtained with the different test versions and formats suggests that it is not necessary to reestablish a baseline viral load when changing AMPLICOR HIV-1 MONITOR tests, unless the patient is known to be infected with a non-B subtype.
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PMID:Assessment of agreement between the AMPLICOR HIV-1 MONITOR test versions 1.0 and 1.5. 1471 66

We compared the performance of two UltraSensitive AMPLICOR HIV-1 MONITOR kits (version 1.5 [v1.5] versus v1.0) by retesting 404 plasma samples with low viral loads (<3,000 copies/ml) with both kits. With 292 samples that initially had <50 copies/ml by the v1.0 kit, the v1.5 assay was more sensitive than the v1.0 assay for samples with human immunodeficiency virus type 1 RNA near the 50-copy/ml cutoff (P = 0.0146). Median numbers of copies per milliliter were similar for 112 samples with 50 to 3,000 copies/ml with no difference in sensitivity with a 200-copy/ml cutoff.
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PMID:Comparison of versions 1.0 AND 1.5 of the UltraSensitive AMPLICOR HIV-1 MONITOR test for subjects with low viral load. 1518 67

The sensitivities of the version 1.5 and 1.0 Roche UltraSensitive AMPLICOR HIV-1 MONITOR tests were compared using panels of coded samples of subtype B human immunodeficiency virus type 1 spiked into plasma at predetermined concentrations. Results indicate that the version 1.5 kit is more sensitive than the version 1.0 kit.
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PMID:Comparison of the sensitivities of the version 1.5 and version 1.0 ultrasensitive Roche AMPLICOR HIV-1 MONITOR kits at low concentrations of human immunodeficiency virus RNA. 1518 81

Rapid quantitative molecular methods are very important for the diagnosis of human immunodeficiency virus (HIV) infections, assessment of prognosis and follow up. The purpose of this study was to compare and evaluate the performances of conventional manual extraction method and automated MagNA Pure system, for the nucleic acid isolation step which is the first and most important step in molecular diagnosis of HIV infections. Plasma samples of 35 patients in which anti-HIV antibodies were found as positive by microparticule enzyme immunoassay and confirmed by immunoblotting method, were included in the study. The nucleic acids obtained simultaneously by manual isolation kit (Cobas Amplicor, HIV-1 Monitor Test, version 1.5, Roche Diagnostics) and automated system (MagNA Pure LC Total Nucleic Acid Isolation Kit, Roche Diagnostics), were amplified and detected in Cobas Amplicor (Roche Diagnostics) instrument. Twenty three of 35 samples (65.7%) were found to be positive, and 9 (25.7%) were negative by both of the methods. The agreement between the methods were detected as 91.4%, for qualitative results. Viral RNA copies detected by manual and MagNA Pure isolation methods were found between 76.0-7.590.000 (mean: 487.143) and 113.0-20.300.0000 (mean: 2.174.097) copies/ml, respectively. When both of the overall and individual results were evaluated, the number of RNA copies obtained with automatized system, were found higher than the manual method (p<0.05). Three samples which had low numbers of nucleic acids (113, 773, 857, respectively) with MagNA Pure, yielded negative results with manual method. In conclusion, the automatized MagNA Pure system was found to be a reliable, rapid and practical method for the isolation of HIV-RNA.
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PMID:[Comparison of manual and automated (MagNA Pure) nucleic acid isolation methods in molecular diagnosis of HIV infections]. 1529 5

Although human immunodeficiency virus type 1 (HIV-1) RNA is the acknowledged "gold standard" marker for monitoring disease activity in patients receiving highly active antiretroviral therapy (HAART), it remains unaffordable in resource-constrained settings. The present study investigated two commercially available kits for the detection of HIV-1 viral load markers as more affordable alternatives to HIV-1 RNA quantitation. The greatly improved heat-denatured, signal-boosted HiSens HIV-1 p24 Ag Ultra kit (Perkin-Elmer) and the ExaVir Load Quantitative HIV-RT kit (Cavidi Tech AB) were compared with the Amplicor HIV-1 Monitor (version 1.5) assay (Roche Molecular Systems Inc.). A total of 117 samples containing HIV-1 subtype C were analyzed by all three methodologies. Eighty-nine of these samples represented serial measurements from 20 patients receiving HAART. The remaining samples analyzed were from a group of treatment-naive patients. The association between the p24 antigen assay and the RNA assay was fairly strong (R(2) = 0.686). The association between the reverse transcriptase (RT) quantitation assay and the RNA assay was strong (R(2) = 0.810). Both alternative assays seemed most useful for the serial monitoring of patients receiving HAART (n = 89 plasma samples from 20 patients), as all assays showed a statistically significant downward trend over time, with the trend being either linear or curvilinear. In addition, all three assays showed negative correlations with the CD4 count (CD4 count versus RNA load, r = -0.336 and P = 0.001; CD4 count versus p24 antigen level, r = -0.541 and P < 0.0001; CD4 count versus RT level, r = -0.358 and P = 0.0006). Still of major concern are both the lack of sensitivity and the wide degrees of variability of both assays. However, both assays provide a less expensive alternative to the Roche viral load assay and demonstrate the same trends during treatment.
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PMID:Evaluation of two commercially available, inexpensive alternative assays used for assessing viral load in a cohort of human immunodeficiency virus type 1 subtype C-infected patients from South Africa. 1569 92


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