Performance characteristics of an instrument-free point-of-care CD4 test (VISITECT®CD4) for use in resource-limited settings

Vairamohan Vidhyavathi, Hussain Syed Iqbal, Kannaiyan Kanthamani, Sunil Suhas Solomon, Paneerselvam Nandagopal, Stanley Luchters, Minh D. Pham, James Forbes, Suzanne M. Crowe, Christopher McMurran, David A. Anderson, Pachamuthu Balakrishnan

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: CD4+ T lymphocyte count remains the most common biomarker of immune status and disease progression in human immunodeficiency virus (HIV)-positive individuals. VISITECT®CD4 is an instrument-free, low-cost point-of-care CD4 test with a cut-off of 350 CD4 cells/μL. This study aimed to evaluate VISITECT®CD4 test's diagnostic accuracy. Methods: Two hundred HIV-positive patients attending a tertiary HIV centre in South India were recruited. Patients provided venous blood for reference and VISITECT®CD4 tests. An additional finger-prick blood sample was obtained for VISITECT®CD4. VISITECT®CD4's diagnostic performance in identifying individuals with CD4 counts ≤350 cells/μL was assessed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) taking flow cytometry as the reference. Results: The overall agreement between VISITECT®CD4 and flow cytometry was 89.5% using venous blood and 81.5% using finger-prick blood. VISITECT®CD4 showed better performance using venous blood [sensitivity: 96.6% (95% confidence interval: 92.1%–98.9%), specificity: 70.9% (57.1%–82.4%), PPV: 89.7% (83.9%–94.0%) and NPV: 88.6% (75.4%–96.2%)] than using finger-prick blood [sensitivity: 84.8% (77.9%–90.2%), specificity: 72.7% (59.0%–83.9%), PPV: 89.1% (82.7%–93.8%) and NPV: 64.5% (51.3%–76.3%)]. Conclusion: VISITECT®CD4 performed well using venous blood, demonstrating its potential utility in decentralization of CD4 testing services in resource-constrained settings.

Original languageEnglish (US)
JournalJournal of International Medical Research
Volume48
Issue number9
DOIs
StatePublished - 2020

Keywords

  • CD4+ count
  • HIV monitoring assay
  • HIV/AIDS
  • VISITECT®CD4 test
  • point-of-care diagnostics
  • resource-limited settings

ASJC Scopus subject areas

  • Biochemistry
  • Biochemistry, medical
  • Cell Biology

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