Accurate CD4 T-cell enumeration and antiretroviral drug toxicity monitoring in primary healthcare clinics using point-of-care testing

Abstract

To evaluate the accuracy of point-of-care tests (POCTs) for CD4 cell, clinical chemistry and hemoglobin in primary healthcare clinics in Mozambique. POCT and laboratory-based assays were conducted on adult HIV-positive patients enrolled consecutively at primary healthcare clinics in Mozambique. Patients were tested on-site with POCT CD4 (Pima), clinical chemistry (Reflotron) and hemoglobin (HemoCue) devices using finger prick blood. Results obtained on paired blood samples were used for agreement analysis (bias and limits of agreement). Repeatability analysis was also performed for POCT CD4 cell counting. Primary health nurses operating the Pima, Reflotron and HemoCue POCT devices produced results with low levels of bias for CD4(+) T-cell counts (-52.8 cells/μl), alanine aminotransferase (-0.2 U/l), aspartate aminotransferase (-4.0 U/l) and hemoglobin (0.95 g/dl). CD4(+) T-cell counts in paired specimens of finger prick and venous blood tested on the POCT CD4 device were in close agreement (bias -9 cells/μl, coefficient of variation 10.6%). The repeatability of POCT CD4 cell counting was similar to that observed with laboratory instruments (bias -6.2 cells/μl, coefficient of variation 10.7% vs. bias -5.7 cells/μl, coefficient of variation 7.5%). Primary health clinic nurses generated accurate results for CD4(+) T-cell counts, liver enzymes and hemoglobin using simple POC devices on finger prick samples at decentralized antiretroviral therapy (ART) clinics. POC diagnostics to monitor ART at primary healthcare level is technically feasible and should be utilized in efforts to decentralize HIV care and treatment.