Nephrolithiasis — Abnormal Metabolic Evaluation — Clinical Pathway: Outpatient Specialty Care

Nephrolithiasis Clinical Pathway — Outpatient Specialty Care

Abnormal Metabolic Evaluation Results

Pending 24-hour results consider the following:

  • 25-OH Vitamin D, parathyroid hormone
  • Genetic testing

Normal Values for Urinary Solute Excretion

Metabolite Age Random
(mg/mg)		 24-h, All Ages
(Litholink, Quest, LabCorp, etc.)
Calcium
0-6 mos < 0.8 < 4 mg/kg/d
7-12 mos < 0.6
> 24 mos < 0.21
Oxalate
0-6 mos < 0.26 < 40 mg/1.73 m2
7-24 mos < 0.11
2-5 yrs < 0.08
5-14 yrs < 0.06
> 16 yrs < 0.03
Citrate
0–17 yrs > 0.2-0.42 Males: > 130 mg/gm
Females: > 300 mg/gm
> 18 yrs Males: > 450 mg/gm
Females: > 550 mg/gm
Cystine > 6 mos < 0.075 < 50 mg/1.73 m2
Uric Acid > 2 yrs 0.56 mg/dL GFR < 815 mg/1.73 m2

Sample is considered normal if:

  • All results fall within normal ranges
  • There are no abnormalities other than low urine volume

Please make sure that you check adequacy of sample based on 24-hour creatinine excretion.