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Performance of Cepheid Xpert HIV-1 viral load plasma assay to accurately detect treatment failure

Sacks, Jilian A.a; Fong, Youyib; Gonzalez, Mercedes Perezc; Andreotti, Maurod; Baliga, Shrikalae; Garrett, Nigelf; Jordan, Jeanneg; Karita, Etienneh; Kulkarni, Smitai; Mor, Ornaj; Mosha, Faustak; Ndlovu, Zibusisol; Plantier, Jean-Christophem; Saravanan, Shanmugamn; Scott, Lesleyo; Peter, Trevora; Doherty, Megc; Vojnov, Larac

doi: 10.1097/QAD.0000000000002303

Background: Coverage of viral load testing remains low with only half of the patients in need having adequate access. Alternative technologies to high throughput centralized machines can be used to support viral load scale-up; however, clinical performance data are lacking. We conducted a meta-analysis comparing the Cepheid Xpert HIV-1 viral load plasma assay to traditional laboratory-based technologies.

Methods: Cepheid Xpert HIV-1 and comparator laboratory technology plasma viral load results were provided from 13 of the 19 eligible studies, which accounted for a total of 3790 paired data points. We used random effects models to determine the accuracy and misclassification at various treatment failure thresholds (detectable, 200, 400, 500, 600, 800 and 1000 copies/ml).

Results: Thirty percent of viral load test results were undetectable, while 45% were between detectable and 10 000 copies/ml and the remaining 25% were above 10 000 copies/ml. The median Xpert viral load was 119 copies/ml and the median comparator viral load was 157 copies/ml, while the log10 bias was 0.04 (0.02–0.07). The sensitivity and specificity to detect treatment failure were above 95% at all treatment failure thresholds, except for detectable, at which the sensitivity was 93.33% (95% confidence interval: 88.2–96.3) and specificity was 80.56% (95% CI: 64.6–90.4).

Conclusion: The Cepheid Xpert HIV-1 viral load plasma assay results were highly comparable to laboratory-based technologies with limited bias and high sensitivity and specificity to detect treatment failure. Alternative specimen types and technologies that enable decentralized testing services can be considered to expand access to viral load.

aClinton Health Access Initiative, Boston, Massachusetts

bFred Hutchinson Cancer Research Center, Seattle, Washington

cWorld Health Organization, Geneva, Switzerland

dNational Center for Global Health, Istituto Superiore di Sanita, Viale Regina Elena, Rome, Italy

eKasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India

fCentre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa

gGeorge Washington University, Washington, District of Columbia, USA

hProject San Francisco/Rwanda-Zambia HIV Research Group, Kigali, Rwanda

iICMR-National AIDS Research Institute, Pune, Maharashtra, India

jCentral Virology Laboratory, Public Health Services, Israel Ministry of Health, Tel – Hashomer, Israel

kNational Health Laboratory Quality Assurance and Training Centre, Dar es Salaam, Tanzania

lMedecins Sans Frontieres, Southern Medical Unit, Cape Town, South Africa

mNormandie University, Unirouen, Rouen University Hospital, Laboratory of Virology, Rouen, France

nY. R. Gaitonde Centre for AIDS Research and Education, Taramani, Chennai, Tamil Nadu, India

oDepartment of Molecular Medicine and Haemotology, School of Pathology, Faculty of Health Science, University of Witwatersrand, Johannesburg, South Africa.

Correspondence to Lara Vojnov, PhD, World Health Organization, Avenue Appia 20. Geneva, Switzerland. Tel: +41 22 791 21 11; e-mail:

Received 28 March, 2019

Revised 7 May, 2019

Accepted 17 May, 2019

Copyright © 2019 Wolters Kluwer Health, Inc.