A leukemia patient was admitted to the hospital for a bone marrow transplant. Calcium boluses were administered before transplantation for hypocalcemia [Ionized calcium: 0.97 mmol/L (3.9 mg/dL); reference interval, 1.05–1.27 mmol/L (4.2–5.1 mg/dL). Total calcium: 2.00 mmol/L (8.0 mg/dL); reference interval, 2.22–2.67 mmol/L (8.9–10.7 mg/dL)].

After undergoing transplantation, the patient developed hypertension and had a low hematocrit and platelet count. His calcium concentration continued to be low despite the calcium administration. By 12 days after transplantation, the patient's ionized calcium concentration was 0.97 mmol/L (3.9 mg/dL) and the total calcium concentration was 2.00 mmol/L (8.0 mg/dL). His albumin concentration was 456.0 mmol/L (3.0 g/dL) [reference interval, 562.4–851.2 mmol/L (3.7–5.6 g/dL)], and the urine calcium:creatinine ratio was 0.65 (upper reference limit, 0.23).

 QUESTIONS

  1. Why did the patient have a low ionized calcium concentration despite a typical total serum calcium concentration and a low albumin concentration?
  2. Why did the patient continue to excrete a large amount of calcium despite hypocalcemia?

What Is Your Guess? Read the article by Hoi-Ying Elsie Yu, et al., here​ ​for the answers.