Sunday, February 7, 2016

Clinical Evaluation of an Affordable Qualitative Viral Failure Assay for HIV Using Dried Blood Spots in Uganda

WHO recommends regular viral load (VL) monitoring of patients on antiretroviral therapy (ART) for timely detection of virological failure, prevention of acquired HIV drug resistance (HIVDR) and avoiding unnecessary switching to second-line ART. However, the cost and complexity of routine VL testing remains prohibitive in most resource limited settings (RLS). We evaluated a simple, low-cost, qualitative viral-failure assay (VFA) on dried blood spots (DBS) in three clinical settings in Uganda.

We conducted a cross-sectional diagnostic accuracy study in three HIV/AIDS treatment centres at the Joint Clinical Research Centre in Uganda. The VFA employs semi-quantitative detection of HIV-1 RNA amplified from the LTR gene. We used paired dry blood spot (DBS) and plasma with the COBASAmpliPrep/COBASTaqMan, Roche version 2 (VLref) as the reference assay. We used the VFA at two thresholds of viral load, (>5,000 or >1,000 copies/ml).

496 paired VFA and VLref results were available for comparative analysis. Overall, VFA demonstrated 78.4% sensitivity, (95% CI: 69.7%-87.1%), 93% specificity (95% CI: 89.7%-96.4%), 89.3% accuracy (95% CI: 85%-92%) and an agreement kappa = 0.72 as compared to the VLref. The predictive values of positivity and negativity among patients on ART for >12 months were 72.7% and 99.3%, respectively.

VFA allowed 89% of correct classification of VF. Only 11% of the patients were misclassified with the potential of unnecessary or late switch to second-line ART. Our findings present an opportunity to roll out simple and affordable VL monitoring for HIV-1 treatment in RLS.

Below:  Receiver Operating Characteristics Curve for VFA compared to Cobas-Ampliprep

Below:  Receiver Operating Characteristics Curve for VFA comparing ART–na├»ve and treated PLWHAs (VL threshold ≥ 5,000 cp/mL)

Full article at:

  • 1Joint Clinical Research Center, P.O. Box 10005, Kampala, Uganda.
  • 2Amsterdam Institute for Global Health and Development, Department of Global Health, Academic medical Center, Trinity C Building, Pietersbergweg 17, 1105 BM, Amsterdam, the Netherlands.
  • 3PharmAccess International, Amsterdam, Trinity Building C Pietersbergweg 17, 1105 BM, Amsterdam, the Netherlands.
  • 4Wits Health Consortium, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein 2000, Johannesburg, South Africa.
  • 5University Medical Centre Utrecht, P.O. Box 80125, 3508 TC, Utrecht, the Netherlands. 
  •  2016 Jan 29;11(1):e0145110. doi: 10.1371/journal.pone.0145110. eCollection 2016.

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