Sikazwe I, et al. - Through a random sample with unknown outcomes due to lack of follow-up gathered from the national electronic medical record system, researchers assessed retention and viral suppression in a large public health program across four provinces in Zambia. Participants were HIV-positive adults 18 years or older who sought HIV care and treatment services over a 24-month period. Imperfect response rates and the use of self-reported care status were limitations. They found that retention was underestimated in routine program data, and when lost patients were accounted for, the point prevalence of unsuppressed HIV RNA was high. Among patients who unofficially transferred, viremia was prevalent: Continuous engagement is still challenging with HIV patients in Zambia; targeted sampling is an efficacious way to recognize gaps in the care cascade and monitor programmatic progress.