• Pooled HIV-1 Viral Load Testing Using Dried Blood Spots to Reduce the Cost of Monitoring Antiretroviral Treatment in a Resource-Limited Setting

      Pannus, Pieter; Fajardo, Emmanuel; Metcalf, Carol; Coulborn, Rebecca M; Durán, Laura T; Bygrave, Helen; Ellman, Tom; Garone, Daniela; Murowa, Michael; Mwenda, Reuben; et al. (Lippincott Williams & Wilkins, 2013-10-01)
      : Rollout of routine HIV-1 viral load monitoring is hampered by high costs and logistical difficulties associated with sample collection and transport. New strategies are needed to overcome these constraints. Dried blood spots from finger pricks have been shown to be more practical than the use of plasma specimens, and pooling strategies using plasma specimens have been demonstrated to be an efficient method to reduce costs. This study found that combination of finger-prick dried blood spots and a pooling strategy is a feasible and efficient option to reduce costs, while maintaining accuracy in the context of a district hospital in Malawi.
    • Prospective Evaluation of the Diagnostic Accuracy of Dried Blood Spots from Finger-Prick for the Determination of HIV-1 Viral Load with the NucliSENS Easy-Q HIV-1 v2.0 in Malawi

      Fajardo, Emmanuel; Metcalf, Carol A; Chaillet, Pascale; Aleixo, Lucia; Pannus, Pieter; Panunzi, Isabella; Triviño, Laura; Ellman, Tom; Likaka, Andrew; Mwenda, Reuben (American Society for Microbiology, 2014-02-05)
      HIV-1 viral load (VL) testing is not widely available in resource-limited settings. Use of finger-prick dried blood spot (FP-DBS) samples could remove barriers related to sample collection and transport. Measurement of VL using DBS from EDTA venous blood (VB-DBS) in place of plasma has previously been validated using the NucliSENS EasyQ HIV-1 v2.0 assay, but information on the accuracy of FP-DBS samples for measuring VL is limited. This prospective study, conducted at Thyolo District Hospital in Southern Malawi, compared VL levels measured on FP-DBS samples and plasma, using the NucliSENS EasyQ HIV-1 v2.0 assay. Comparability was assessed by means of agreement and correlation (131 patients with VLs ≥100 copies/ml), and sensitivity and specificity (612 patients on ART). Samples of EDTA venous blood and FP-DBS from 1,009 HIV-infected individuals were collected and prepared in the laboratory. Bland-Altman analysis found good agreement between plasma and FP-DBS VL levels, with a mean difference of -0.35 log10, and 95% limits of agreement from -1.26 to 0.55 log10. FP-DBS had a sensitivity of 88.7% (95% confidence interval [CI]: 81.1 - 94.4%) and specificity of 97.8% (95% CI: 96.1 - 98.9%) using a 1,000 copies/ml cut-point; and a sensitivity of 83.0% (95% CI: 73.4 - 90.1%) and specificity of 100% (95% CI: 99.3-100%) using a 5,000 copies/ml cut-point. This study shows that FP-DBS is an acceptable alternative to plasma for measuring VL using the NucliSENS EasyQ HIV-1 v2.0. We are conducting a second study to assess the proficiency of health workers at preparing FP-DBS in primary healthcare clinics.