Clinicians interpreting CD4 cell count and percentage in children must consider age as a factor. CD4 cell
count and percentage values in healthy infants who are HIV-uninfected are considerably higher than values
observed in uninfected adults and slowly decline to adult values by age 5 years.1,2 In children younger than
age 5 years, the absolute CD4 cell count tends to vary more with age than does CD4 percentage. Therefore,
in HIV-infected children younger than age 5 years, CD4 percentage has generally been preferred for
monitoring immune status, whereas absolute CD4 cell count has been the preferred option for children aged
≥5 years