Field evaluation of PIMA point-of-care CD4 testing in Rakai, Uganda.

To assess the accuracy of PIMA Point-of-Care (POC) CD4 testing in rural Rakai, Uganda.903 HIV positive persons attending field clinics provided a venous blood sample assessed on site using PIMA analyzers per manufacturer's specifications. The venous samples were then run on FACSCalibur flow cytometry at a central facility. The Bland-Altman method was used to estimate mean bias and 95% limits of agreement (LOA). Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated for a CD4 threshold of