A client with chronic kidney disease (CKD) is receiving calcium acetate 667 mg PO. A decrease in which blood value indicates to the nurse that the medication is having the desired effect?

A. pH levels are not directly affected by calcium acetate and do not indicate the medication's effectiveness. B. Calcium acetate is used to lower phosphate levels in patients with CKD, so a decrease in phosphate indicates that the medication is having the desired effect. C. Potassium levels are not directly impacted by calcium acetate and do not reflect the medication’s effectiveness in managing phosphate levels. D. Calcium levels are not the primary target of calcium acetate therapy; the focus is on reducing phosphate levels in CKD management.