Other strengths of the study include a relatively large sample size, the exclusion of children with concomitant infections (a factor known to cause transient albuminuria), the measurement of urinary albumin in fresh (not frozen) urine samples by a single central laboratory, and the evaluation of albuminuria not only on the base of UAC but also of UACR (as the latter corrects for urine dilution). Here, ALB is linked to infection.