Healthy volunteers
Not accepted
Inclusion Criteria:
* Inclusion criteria include pediatric patients, between the ages of 2 and 21 years, with CKD stages 2-4 (GFR 15-90 ml/min/1.73m2).
Exclusion Criteria:
* Exclusion criteria include: the use of phosphate binder therapy within the past 3 months, treatment with 25(OH)vitamin D or 1,25dihydroxyvitamin D, underlying metabolic bone disease, or underlying renal phosphate wasting disorder.
