Clinical Research Directory

Inclusion Criteria: All groups : * Minor patients (\<18 years) * Patients of both sexes * Informed patients and parents who have signed the informed consent form * Patients affiliated to social security Control group : \- Patients with no particular pathology undergoing surgery and receiving a preoperative check-up CKD groups : * Patients on dialysis for more than 3 months, regardless of technique * Kidney transplant patients * Patients with CKD, whatever the cause Exclusion Criteria: * Progressive cancer or kidney disease * Treatments that may modify PPi concentration (e.g. bisphosphonates)