Peritoneal dialysis with calcium free dialysis solution has been reported to lower effectively total serum calcium concentration in hypercalcemic patients.1,2 Lack of availability of calcium free solutions most likely explains infrequent reports of use of this form of therapy in spite of frequent need to treat hypercalcemia in the presence of impaired renal function and in spite of the relative safety and technical simplicity of the procedure.
Commercially available dialysis solutions contain ionized calcium concentrations higher than those in normal serum and do not provide a maximum concentration gradient for diffusion of calcium from peritoneal capillary blood. In fact, calcium absorption usually occurs from such solutions during dialysis in patients with chronic renal disease and low serum calcium concentrations.3
This study describes a patient with vitamin D intoxication and severely impaired renal function who underwent repeated peritoneal dialyses with calcium free peritoneal dialysis solutions. Changes in serum total