Urinary calcium-to-citrate ratio predicts kidney stone risk in children under the age of two years

In infants and toddlers evaluated for suspected urinary stone disease, the Ca/Cit ratio offers moderate discriminatory power and may serve as a practical adjunctive marker of stone risk. A ratio > 0.23 mg/mg (≈ 1.10 mmol/mmol) appears to indicate increased lithogenic potential. Larger prospective studies are needed to validate reference intervals and refine clinically applicable cut-off values for this young age group.