The diagnostic performance of the Visitect Advanced Disease point-of-care CD4 platform: a pragmatic mixed-methods multisite validation, costing, and qualitative analysis

Elizabeth Nalintya; Preethiya Sekar; Olive L Namakula; Kiiza Kandole Tadeo; Richard Kwizera; Lucy Apeduno; Diana Rose Naluyima; Rachel Nanano; Lilian Mujungu; Alice Lehman; Tessa Adzemovic; Mathius Amperiize; Paul Kavuma; Viola Kasone; Ann Fieberg; Patricia Nerima; Biyue Dai; David B Meya; David R Boulware; Radha Rajasingham

doi:10.1097/QAI.0000000000003505

The diagnostic performance of the Visitect Advanced Disease point-of-care CD4 platform: a pragmatic mixed-methods multisite validation, costing, and qualitative analysis

J Acquir Immune Defic Syndr. 2024 Aug 19. doi: 10.1097/QAI.0000000000003505. Online ahead of print.

Authors

Elizabeth Nalintya¹, Preethiya Sekar², Olive L Namakula¹, Kiiza Kandole Tadeo¹, Richard Kwizera¹, Lucy Apeduno¹, Diana Rose Naluyima¹, Rachel Nanano¹, Lilian Mujungu¹, Alice Lehman³, Tessa Adzemovic¹, Mathius Amperiize¹, Paul Kavuma¹, Viola Kasone⁴, Ann Fieberg⁵, Patricia Nerima¹, Biyue Dai⁵, David B Meya^{1

6}, David R Boulware³, Radha Rajasingham³

Affiliations

¹ Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda.
² University of Minnesota Medical School, Minneapolis, Minnesota, USA.
³ Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.
⁴ National Health Laboratory and Diagnostic Services, Ministry of Health, Kampala, Uganda.
⁵ Division of Biostatistics, University of Minnesota, Minneapolis, Minnesota, USA.
⁶ Department of Medicine, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda.

PMID: 39159398
DOI: 10.1097/QAI.0000000000003505

Abstract

Background: The Visitect CD4 Advanced Disease test (AccuBio, Alva, United Kingdom) is a rapid, semi-quantitative assay that estimates CD4 results above or below 200 cells/μL. We evaluated the performance of the Visitect CD4 assay in semi-urban laboratories in Uganda.

Methods: We performed a pragmatic laboratory validation of the Visitect CD4 platform in four routine HIV clinics in Uganda, nested within a cluster randomized trial evaluating an enhanced package of screening and treatment for persons with advanced HIV disease (NCT05085171). As part of the clinical trial, samples processed on the Visitect CD4 platform were confirmed using another CD4 testing method. We compared the diagnostic performance of the Visitect CD4 platform against the confirmatory method by evaluating the sensitivity, specificity, positive and negative predictive values.

Results: Of 1495 venous blood samples that were processed both by the Visitect CD4 test and another confirmatory CD4 platform at clinics in Kampala, Uganda, specificity was 81% (95% CI, 79%-84%) and the positive predictive value was 69% (95% CI, 66%-73%). There were no samples for which the Visitect test was >200 cells/μL and the confirmatory test was ≤200 cells/μL, resulting in a sensitivity of 100%. Among Visitect CD4 tests that were read as <200 cells/μL with confirmatory results >200 cells/μL, the median confirmatory CD4 result was 397 (IQR, 281-590) cells/μL. Specificity varied by clinic ranging from 63% to 99%.

Conclusions: Given variable specificity of the Visitect CD4 Advanced Disease platform, successful implementation will require consideration of clinic context and laboratory staffing.