Can Iron Transfusion Cause Hypercalcemia?
No, iron transfusion does not cause hypercalcemia—in fact, intravenous iron therapy is associated with hypocalcemia and hypophosphatemia, not elevated calcium levels.
The Actual Electrolyte Disturbances from Iron Therapy
Iron infusions cause the opposite problem: they precipitate hypocalcemia and hypophosphatemia, not hypercalcemia 1. A recent case report documented severe hypocalcemia and hypophosphatemia following parenteral iron administration, resulting in respiratory failure from muscle weakness and cardiac arrhythmia requiring noninvasive ventilation and urgent intravenous electrolyte replacement 1.
What Blood Transfusions Actually Cause
When discussing transfusion-related electrolyte disturbances, the relevant concerns are:
- Hypocalcemia (not hypercalcemia): Blood products contain citrate preservative that binds calcium, and ionized calcium levels should be monitored and maintained within normal range during massive transfusion 2
- Hyperkalemia: Each unit of packed red blood cells contains approximately 0.9 mEq/Kg of potassium, which can accumulate with rapid transfusion 2
- Iron overload: Each unit of packed red blood cells contains 200-250 mg of elemental iron that accumulates with no active excretion mechanism 3
True Causes of Hypercalcemia
Approximately 90% of hypercalcemia cases are due to primary hyperparathyroidism or malignancy 4. Other causes include granulomatous diseases like sarcoidosis, endocrinopathies, immobilization, genetic disorders, thiazide diuretics, and calcium/vitamin D supplements 4.
Critical Clinical Pitfall
Do not confuse iron overload complications with hypercalcemia. Iron overload from chronic transfusions causes cardiac disease (70% of deaths in transfusion-dependent patients), liver fibrosis and cirrhosis, and endocrine dysfunction including hypothyroidism and diabetes 3. These are distinct from hypercalcemia, which presents with fatigue, constipation, nausea, vomiting, confusion, and in severe cases (≥14 mg/dL), somnolence and coma 4.
When to Monitor Electrolytes with Transfusions
- Monitor ionized calcium during massive transfusions due to citrate-induced hypocalcemia 2
- Monitor potassium in patients receiving rapid transfusions or those with cardiac dysfunction 2
- Monitor for iron overload with serum ferritin in chronically transfused patients, particularly those with sickle cell disease or thalassemia 5