Performance of a True Point-of-Care Assay for HIV-1/2 Viral Load Measurement at Antenatal and Postpartum Services

Background: Timely viral load (VL) results during pregnancy and the postpartum period are crucial for HIV disease management and for preventing mother-to-child transmission. Point-of-care (POC) VL testing could reduce turnaround times and streamline patient management. We evaluated the diagnostic performance of the novel m-PIMA HIV-1/2 VL assay (Abbott, Chicago, IL) in Mozambique. Setting: The study was conducted in prenatal and postpartum consultation rooms in 2 primary health care clinics. Sample collection and testing on m-PIMA were performed by trained nurses. Methods: HIV-infected pregnant and postpartum women on antiretroviral treatment (ART) or ART naive were tested using both on-site m-PIMA POC and referral laboratory-based real-time VL assays. Linear regression analysis and Bland-Altman plots were used to calculate the agreement between both. Findings: Correlation between venous blood plasma POC and plasma laboratory-based VL was strong (r(2) = 0.850, P < 0.01), with good agreement between the methods [overall bias 0.202 log copies/mL (95% CI: 0.366 to 0.772 log copies/mL)]. Using the threshold of 1000 copies/mL, which is used to determine ART failure, the sensitivity and specificity of the POC VL assay were 95.0% (95% CI: 91.6% to 97.3%) and 96.5% (95% CI: 94.2% to 98.0%), respectively. The correlation coefficient between the venous and capillary sample types was 0.983 (r(2) = 0.966). Conclusions: On-site, nurse-performed POC VL testing is feasible and accurate in resource-limited primary health care settings. The operational challenge of plasma separation within clinics for POC testing was successfully overcome using minicentrifuges. The use of capillary blood could simplify the execution of the assay in a clinical environment.