VISITECT® CD4 advanced disease assay in routine use: Diagnostic accuracy and usability, Ethiopia and Indonesia.

We assessed the diagnostic accuracy and usability of the rapid semiquantitative point of care VISITECT® CD4 Advanced Disease Assay, compared to routinely obtained CD4 counts among people living with HIV in Ethiopia and Indonesia. We consecutively enrolled people living with HIV aged ≥10 years who were newly diagnosed, had interrupted antiretroviral treatment for ≥3 months, or were feeling unwell. Venous blood was drawn to obtain CD4 counts on routinely available test instruments and a VISITECT® CD4 Advanced Disease Assay result. The sensitivity of VISITECT® CD4 Advanced Disease Assay was high (97.8%, 95% confidence interval [CI], 94.4-99.4%), but the specificity was low (32.7%, 95%CI, 27.9-37.8%). It significantly increased to 42.5% (95%CI, 33.2-52.1%) after retraining of laboratory staff, but remained low. The low specificity of VISITECT® CD4 Advanced Disease Assay was due to poor capacity in test reading by routine staff. Reading the test strip is error-prone and requires intensive and regular training. Reading aids may improve the usability of this essential point of care test.