Spot urinary creatinine excretion in pervasive developmental disorders.

Background: Excretion of creatinine in urine represents the end-point of endogenous energy transfer from stored adenosine triphosphate in skeletal and cardiac muscle. Measurement of urinary creatinine is commonly used to correct for total urine concentration. Various quantitative measures of compounds suspected to be either pathological to, or indicative of, possible therapeutic interventions for Pervasive Developmental Disorders (PDD) have relied extensively on spot creatinine as a ratio quantity, although this important metabolite has not been exclusively studied within this population.