Using Exclusion-Based Sample Preparation (ESP) to Reduce Viral Load Assay Cost

Scott M. Berry, Hannah M. Pezzi, Eram D. Williams, Jennifer M. Loeb, David J. Guckenberger, Alex J. LaVanway, Alice A. Puchalski, Cissy M. Kityo, Peter N. Mugyenyi, Franklin M. Graziano, David J. Beebe

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Viral load (VL) measurements are critical to the proper management of HIV in developing countries. However, access to VL assays is limited by the high cost and complexity of existing assays. While there is a need for low cost VL assays, performance must not be compromised. Thus, new assays must be validated on metrics of limit of detection (LOD), accuracy, and dynamic range. Patient plasma samples from the Joint Clinical Research Centre in Uganda were de-identified and measured using both an existing VL assay (Abbott RealTime HIV-1) and our assay, which combines low cost reagents with a simplified method of RNA isolation termed Exclusion-Based Sample Preparation (ESP).71 patient samples with VLs ranging from <40 to >3,000,000 copies/mL were used to compare the two methods. We demonstrated equivalent LOD (~50 copies/mL) and high accuracy (average difference between methods of 0.08 log, R2 = 0.97). Using expenditures from this trial, we estimate that the cost of the reagents and consumables for this assay to be approximately $5 USD. As cost is a significant barrier to implementation of VL testing, we anticipate that our assay will enhance access to this critical monitoring test in developing countries.

Original languageEnglish
Article numbere0143631
JournalPLoS ONE
Issue number12
StatePublished - Dec 1 2015

Bibliographical note

Publisher Copyright:
© 2015 Berryet al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

ASJC Scopus subject areas

  • General


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