Which laboratory monitoring is commonly needed with phosphorus to assess bone-mineral balance in PD patients?

• A. Glucose
• B. Sodium
• C. Potassium
• D. Calcium and PTH

Answer: (D)

Bone-mineral balance in peritoneal dialysis hinges on the interplay between phosphorus, calcium, and parathyroid hormone. When phosphorus rises in CKD, it can lower calcium levels and stimulate PTH release. PTH then drives bone turnover and calcium mobilization, while calcium levels feedback to regulate PTH secretion. Monitoring calcium and PTH alongside phosphorus provides a full picture of bone turnover and mineral storage, guiding treatments like phosphate binders, vitamin D therapies, or calcimimetics to maintain normal bone health and reduce vascular calcification risk. Measuring phosphorus alone won’t reveal whether bone turnover is high or low or how calcium balance is being managed, so tracking both calcium and PTH is essential for assessing bone-mineral balance in PD patients.