Artifactual hypercalcaemia in multiple myeloma

We present the clinical course and laboratory findings of a 65 year-old woman with diabetes, osteoporosis and multiple traumatic fractures, who was found to have asymptomatic hypercalcaemia. Extensive work-up disclosed the diagnosis of multiple myeloma. Intact parathyroid hormone was normal despite severe hypercalcaemia. Aggressive treatment with hydration, furosemide, glucocorticoids, bisphosphonate and calcitonin failed to normalize serum calcium level. Free calcium level was only minimally elevated. A normal intact PTH in the face of high corrected serum calcium and the presence of elevated serum proteins should alert the treating physician to the possibility of artifactual hypercalcaemia