Pediatric primary urolithiasis: Symptoms, medical management and prevention strategies

Table 1 Normal values for random urine and 24-h urine factors for children and adolescents

	24-h urine	Random urine corrected by creatinine		Random urine factored for GFR
Volume	≥ 1.0 mL/kg per hour
Creatinine	2 to 3 yr: 6 to 22 mg/kg > 3 yr: 12 to 30 mg/kg
Calcium	< 4.0 mg/kg (0.10 mmol/kg)	Age	mg/mg; mmol/mmol	< 0.10
		0-6 mo	< 0.80; < 2.24
		6-12 mo	< 0.60; < 1.68
		1-2 yr	< 0.40; < 1.12
		2-18 yr	< 0.21; < 0.56
Citrate	≥ 400 mg/g creatinine	≥ 0.28 (mmol/L/mmol/L)		> 0.18 (mg/L/mg/L)
Calcium/Citrate	< 0.33	< 0.33
Na/K	≤ 3.5	≤ 3.5
Uric acid	< 815 mg/1.73 m2 BS	< 0.65		< 0.56 mg < 0.03 mmol
Cystine	< 60 mg/1.73 m2 BS	< 0.02 (mg/mg)
		< 0.01 (mmol/mmol)
Magnesium	> 88 mg/1.73 m2 BS
Oxalate	< 50 mg/1.73 m2 BS	Age	(mg/mg)
	< 0.49 mmol/1.73 m2 BS
		0-6 mo	< 0.30
		7 mo-4 yr	< 0.15
		> 4 yr	< 0.10
Phosphate	TP/GFR: > 2.8 and < 4.4 mg/dL1

¹Phosphate tubular reabsorption by glomerular filtration rate. GFR: Glomerular filtration rate; BS: Body surface.