Which laboratory finding indicates the desired outcome of calcium acetate therapy?

Which laboratory finding indicates the desired outcome of calcium acetate therapy?

• A. Serum phosphorus 6.5 mg/dL.
• B. Serum phosphorus 4.0 mg/dL.
• C. Serum calcium 9.0 mg/dL.
• D. Serum calcium 12 mg/dL.

Answer: (B)

Calcium acetate works as a phosphate binder in the gut, so the goal of therapy is to lower serum phosphate toward normal levels. A phosphorus level of 4.0 mg/dL reflects that desired effect, indicating diminished phosphate absorption. A value of 6.5 mg/dL shows ongoing hyperphosphatemia, meaning the therapy isn’t achieving the target. Calcium levels around 9.0 mg/dL are acceptable and normal but don’t directly demonstrate the binder’s effectiveness, and a calcium level of 12 mg/dL signals hypercalcemia risk, which is undesirable with calcium-based binders.