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1.
J Clin Virol ; 140: 104839, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33991979

RESUMO

BACKGROUND: Measurement of HIV-1 viral load (VL) is essential for monitoring antiretroviral treatment (ART) efficacy. In remote settings, dried blood spots (DBS) may be used as the specimen type. However, cellular components in DBS not present in the gold standard specimen type, plasma, may result in low specificity i.e., over-estimation of VL results from DBS compared to plasma. The Abbott RealTime HIV-1 assay system has been reported to have improved specificity using DBS compared to other tests. A new specimen collection matrix, the cobas plasma separation card (PSC, Roche Molecular Systems), enables specimen collection from a finger prick or venous blood, using a multi-layer absorption and filtration design that results in a specimen similar to plasma. OBJECTIVES AND STUDY DESIGN: We performed a direct comparison between VL results from PSC tested with the cobas 6800/8800 assay (c8800) and DBS tested with the Abbott RealTime HIV-1 assay. RESULTS: Overall concordance between PSC and plasma around the 1000 copies/mL threshold was high (>97%). Compared to VL measured using DBS and the RealTime assay, PSC and c8800 showed improved sensitivity (96.9% vs 90.6%) and specificity (97.4% vs. 87.2%) using plasma as the reference, as there were fewer patients with VL below 1000 copies/mL in plasma in whom VL was over this threshold using PSC compared to DBS. The limit of detection for PSC was lower than for DBS (575 vs. 2314 copies/mL). CONCLUSIONS: cobas PSC represents a promising specimen type for use with the cobas 6600/8800 system in settings where plasma cannot be used.


Assuntos
Infecções por HIV , HIV-1 , Teste em Amostras de Sangue Seco , Infecções por HIV/tratamento farmacológico , HIV-1/genética , Humanos , RNA Viral , Sensibilidade e Especificidade , Manejo de Espécimes , Falha de Tratamento , Carga Viral
2.
J Clin Microbiol ; 57(4)2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30728197

RESUMO

Plasma HIV viral load testing is the preferred means of monitoring antiretroviral treatment response. Dried blood spots (DBSs) hold considerable logistical advantages over EDTA samples, but they more frequently misclassify virological failure and have higher limits of detection (LoD). Plasma separation cards (PSCs) may overcome these limitations. Health workers collected EDTA whole blood by venipuncture and 140 µl of finger-prick blood by capillary tube from 53 HIV-infected adults. Capillary blood was immediately transferred to PSCs. Additionally, 432 EDTA samples from HIV-infected adults were spotted onto PSCs and analyzed together with the finger-prick samples. Specificity and sensitivity of PSC with paired EDTA-PSC samples tested on a cobas 6800/8800 system with the cobas HIV-1 test (cobas HIV) was determined. LoD (3rd HIV-1 WHO International Standard) and stability at a range of temperatures and storage durations was determined using cobas HIV and cobas AmpliPrep/cobas TaqMan HIV-1 test v2.0 (CAP/CTM). Of 132 specimens with quantitative values for paired EDTA-PSC samples, the mean log10 difference between samples was 0.05 copies/ml (95% confidence interval [CI], -0.01 to 0.11). The LoD for cobas HIV was 790.2 copies/ml and for CAP/CTM was 737.9 copies/ml. At 1,000 copies/ml, PSC sensitivity was 97.0% (128/132) and specificity was 97.2% (343/353). Results correlated well with those from EDTA samples (Deming R2 = 0.90). PSC results were unaffected by temperature and storage conditions. PSC samples correlate well with plasma viral load and have adequate sensitivity and specificity. The improved performance may be as a result of a reduction in contribution from cell-associated viral nucleic acids. The card provides an alternative sample collection technology to DBSs.


Assuntos
Teste em Amostras de Sangue Seco/normas , HIV-1/isolamento & purificação , Plasma/virologia , RNA Viral/sangue , Manejo de Espécimes/instrumentação , Carga Viral/métodos , Adulto , Coleta de Amostras Sanguíneas , Filtração/instrumentação , Filtração/métodos , Infecções por HIV/sangue , Infecções por HIV/diagnóstico , Humanos , Limite de Detecção , Papel , RNA Viral/isolamento & purificação , Sensibilidade e Especificidade , Manejo de Espécimes/métodos , Temperatura , Carga Viral/instrumentação
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