Calcium and Vitamin D in CKD

A calcium result is a physiologic signal, not a diagnosis. In chronic kidney disease (CKD), interpret calcium with phosphate, parathyroid hormone (PTH), alkaline phosphatase, kidney function, vitamin D status, symptoms, medications and the direction of change over time. CKD-related mineral and bone disorder (CKD-MBD) is a linked disturbance: declining kidney function reduces phosphate excretion and alters vitamin D metabolism; the resulting changes in calcium, phosphate and PTH affect bone turnover and can contribute to vascular or valvular calcification. The pattern varies with CKD severity, dialysis, diet and treatment, so one value should not drive a treatment decision. The central safety question is whether the patient is stable. Tetany, laryngospasm or stridor, seizure, a prolonged QT interval, ventricular dysrhythmia or altered mental status can accompany dangerous calcium disturbance. These findings require emergency action, not an outpatient recheck. Stable patients still need a structured review of trends and modifiable causes before therapy is changed. Canadian laboratories report calcium in mmol/L. The laboratory's own reference interval and assay information govern interpretation because methods and reference limits vary. Provincial or territorial NP authority, the...