Answer – ICD-10 Code Z21 As stipulated in the diagnosis classification system created by Center for Disease Control and Prevention (CDC), ICD-10 Code Z21 is to be applied to indicate asymptomatic positive human immunodeficiency virus [HIV] infection status. That is, when a patient with no history or complaint of symptoms tests positive for HIV.
As people are always dying and babies are always being born so doctors don’t know the exact figure of the population, just an estimate. hope this helps x
