Diagnostic accuracy of point-of-care VISITECT CD4 Advanced Disease compared to Alere Pima CD4, performed at point-of-care within the advanced HIV disease care package

Abstract

People with advanced HIV disease (AHD) (CD4 <200 cells/μl or World Health Organization stage III/IV conditions in those >5 years) have high mortality. CD4 testing is needed to implement the AHD care package. VISITECT® CD4 Advanced Disease (VISITECT; AccuBio Limited, UK) is a semiquantitative test showing a CD4 result of ≤200 cells/μL or >200 cells/μL. VISITECT had a 95% (95%CI 92-97%) sensitivity and 85% (95%CI 83-86%) specificity when tested on venous blood in laboratory conditions. We assessed VISITECT’s diagnostic accuracy compared to Alere PIMA CD4 (PIMA, Abbott, US), during pragmatic implementation at point-of care, within the AHD care package. We are conducting a prospective, multi-centre community-based active tuberculosis case-finding trial (TB TRIAGE+ TRIAL, NCT05526885). In South Africa we are testing a subset of PWH with PIMA (reference test, gives exact CD4 count) and VISITECT (index test, requires visual comparison of test line to 200-reference line). Nurses performing clinical evaluations and TB triage tests, also perform the two CD4 tests on the same venous blood sample, and if PIMA indicates a CD4≤200cells/μL, urine tuberculosis lipoarabinomannan and cryptococcal antigen testing.