Evaluation of the performance of Abbott m2000 and Roche COBAS Ampliprep/COBAS Taqman assays for HIV-1 viral load determination using dried blood spots and dried plasma spots in Kenya.

Routine HIV viral load testing is not widely accessible in most resource-limited settings, including Kenya. To increase access to viral load testing, alternative sample types like dried blood spots (DBS), which overcome the logistic barriers associated with plasma separation and cold chain shipment need to be considered and evaluated. The current study evaluated matched dried blood spots (DBS) and dried plasma spots (DPS) against plasma using the Abbott M 2000 (Abbott) and Roche Cobas Ampliprep/Cobas TaqMan (CAP/CTM) quantitative viral load assays in western Kenya.Matched plasma DBS and DPS were obtained from 200 HIV-1 infected antiretroviral treatment (ART)-experienced patients attending patient support centers in Western Kenya. Standard quantitative assay performance parameters with accompanying 95% confidence intervals (CI) were assessed at the assays lower detection limit (400cps/ml for CAP/CTM and 550cps/ml for Abbott) using SAS version 9.2. Receiver operating curves (ROC) were further used to assess viral-load thresholds with best assay performance (reference assay CAP/CTM plasma).Using the Abbott test, the sensitivity and specificity, respectively, for DPS were (97.3%, [95%CI: 93.2-99.2] and 98.1% [95%CI: 89.7-100]) and those for DBS (93.9% [95%CI: 88.8-97.2] and 88.0% [95%CI: 82.2-92.4]). The correlation and agreement using paired plasma and DPS/DBS were strong, with r2 = 90.5 and rc = 68.1. The Bland-Altman relative percent change was 95.3 for DPS, (95%CI: 90.4-97.7) and 73.6 (95%CI: 51.6-86.5) for DBS. Using the CAP/CTM assay, the sensitivity for DBS was significantly higher compared to DPS (100.0% [95% CI: 97.6-100.0] vs. 94.7% [95%CI: 89.8-97.7]), while the specificity for DBS was lower: 4%, [95% CI: 0.4-13.7] compared to DPS: 94.0%, [95% CI: 83.5-98.7]. When compared under different clinical relevant thresholds, the accuracy for the Abbott assay was 95% at the 1000cps/ml cut-off with a sensitivity and specificity of 96.6% [95% CI 91.8-98.7] and 90.4% [95% CI 78.2-96.4] respectively. The optimum threshold was at 3000 cps/ml with an accuracy of 95.5%, sensitivity and specificity of 94.6% [95%CI 89.3-97.5] and 98.1% [95%CI 88.4-99.9]) respectively. The best threshold for CAP/CTM was at 4000 copies /mL, with 92.5% accuracy (sensitivity of 96.0% [95%CI 91.0-98.3] and specificity of 82.7% [95%CI 69.2-91.3]).There was similar performance between matched DBS, DPS and plasma using the Abbott test, and good correlation for matched DPS and plasma using the CAPCTM test. The findings suggest that DBS and DPS may be reliably used as alternative specimens to plasma to measure HIV-1 VL using Abbott, and DPS may be reliably used with CAP/CTM in resource-limited settings

HIV-1 RNA detection rates of dried plasma spot (DPS) specimens paired with plasma specimens prepared from patient support centers in Nyanza, Kenya.

<p>(November 2012 to February 2013).</p

Comparisons between CAP/CTM dried blood spot and Abbott dried blood spot tests at different cut-offs using CAP/CTM plasma as the gold standard.

<p>Comparisons between CAP/CTM dried blood spot and Abbott dried blood spot tests at different cut-offs using CAP/CTM plasma as the gold standard.</p

Concordance correlation analyses of HIV-1 viral load (VL) quantification among plasma and dried plasma spot specimens collected from patients visiting Nyanza patient support centers and tested with CAP/CTM and Abbott.

<p><b>a)</b> CAP/CTM plasma vs. DPS VL; <b>b</b>) Abbott plasma vs. DPS VL.</p

HIV-1 RNA detection rates of dried blood spot (DBS) specimens paired with plasma specimens prepared from patient support centers in Nyanza, Kenya.

<p>(November 2012 to February 2013).</p

High Level of HIV Drug Resistance and Virologic Nonsuppression among Female Sex Workers in Ethiopia : A Nationwide Cross-Sectional Study

Objective:To determine viral load (VL) nonsuppression (VLN) rates, HIV drug resistance (HIVDR) prevalence, and associated factors among female sex workers (FSWs) in Ethiopia.Methods:A cross-sectional biobehavioral survey was conducted among FSWs in 11 cities in Ethiopia in 2014. Whole blood was collected, and HIVDR genotyping was performed. Logistic regression analysis was performed to identify factors associated with VLN and HIVDR.Results:Among 4900 participants, 1172 (23.9%) were HIV-positive and 1154 (98.5%) had a VL result. Participants were categorized into antiretroviral therapy (ART) (n = 239) and ART-naive (n = 915) groups based on self-report. From the 521 specimens (ART, 59; ART-naive, 462) with VL ≥1000 copies/mL, genotyping was successful for 420 (80.6%) and 92 (21.9%) had drug resistance mutations (DRMs). Pretreatment drug resistance (PDR) was detected in 16.5% (63/381) of the ART-naive participants. Nucleoside reverse transcriptase inhibitor (NRTI), non-NRTIs (NNRTIs), and dual-class DRMs were detected in 40 (10.5%), 55 (14.4%), and 35 (9.2%) of the participants, respectively. Among 239 participants on ART, 59 (24.7%) had VLN. Genotyping was successfully performed for 39 (66.1%). DRMs were detected in 29 (74.4%). All 29 had NNRTI, 23 (79.3%) had NRTI or dual-class DRMs. VLN was associated with age 35 years or older, CD4+T-cell count <350 cells/mm3, and being forced into selling sex. PDR and acquired drug resistance were associated with CD4+T-cell count <350 cells/mm3(P < 0.001).Conclusions:The high VLN and HIVDR rates among FSWs underscore the need for targeted interventions to improve ART access and virologic monitoring to maximize the benefit of ART and limit the spread of HIV and HIVDR

Concordance correlation analyses of HIV-1 (VL) quantification among plasma and DBS specimens collected from patients visiting Nyanza patient support centers and tested with CAP/CTM and Abbott.

<p><b>a)</b> CAP/CTM plasma vs. DBS VL; <b>b</b>) Abbott plasma vs. DBS VL.</p

Probit analysis for Abbott dried blood spot viral load limit of detection.

<p>Limit of detection 1,222copies/mL, 95% CI (978.12, 1873.7).</p

Bland-Altman analyses to evaluate agreement in HIV-1 viral load (VL) quantification among plasma and dried plasma spot specimens collected from patients visiting Nyanza patient support centers and tested with CAP/CTM and Abbott.

<p>The difference between the reference and the comparison specimen type were plotted against the average of the reference group and the comparison specimen type <b>a</b>) CAP/CTM DPS VL; <b>b</b>) Abbott DPS VL.</p

Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) (95% confidence intervals) of dried blood spot (DBS) and dried plasma spot (DPS) compared with paired plasma specimen VL, patient support centers, Nyanza, Kenya.

<p>(November 2012 to February 2013).</p