On the Urinary Excretion of a Substance as Predicted from the Substance-to-Creatinine Ratio

Equations predicting the urinary excretion of a substance of interest have been developed from a deterministic model linking substance-to-creatinine ratio with expected creatinine output for sex and age. Developed predictive equations show ≥ 80% accuracy and ≥ 90% agreement with traditional, established methods recurring to 24 hours urine collections. Clinical usefulness of the predictive equations has been validated in the study of calcium metabolism disorders. Predictive equations can be expanded to accommodate the specific gravity and osmolarity of urine. Predictive equations discussed in this essay have opened new windows in the assessment of kidney function and metabolic disorders. It is expected these predictive equations to secure a higher compliance of kidney assessment tests in children and adolescents