Hydroxyproline Indices

Abstract

WHEN it was known that the excretion of hydroxyproline peptides in the urine was correlated with active growth, and varied in a characteristic way with age^1–3, Alison et al.⁴ demonstrated that as a measure of growth the ratio of hydroxyproline : creatinine in a 24 h collection of urine was a great improvement on the hydroxyproline excretion/24 h, because the former eliminated to a great extent the effects of weight, and gave more consistent results for subjects of the same age. They found that the ratio fell in children between 1 and 5 yr, and then remained constant until puberty, after which it fell again to the adult level. Jasin et al.¹ had already introduced the factor of surface area to try to eliminate the effects of size, and had found that the results obtained were constant between the ages of 1 and 10 yr.