Use of oral stable strontium to provide an index of intestinal calcium absorption in chronic ambulatory peritoneal dialysis patients

Recent interest in the role of oral calcium carbonate and low calcium dialysate has emphasised the need for a simple, safe and inexpensive test of intestinal calcium absorption. The stable, non-radioactive, strontium absorption test fits these requirements. Stable strontium and calcium-45 were administered simultaneously to 19 fasting CAPD patients and their serum levels were subsequently measured. There was a close correlation between the absorption of calcium and strontium at both 60 and 120 min post-ingestion. The two markers resulted in the same classification of patients as normal or malabsorbers in 18 of 19 cases (95%), suggesting that strontium could be substituted for calcium-45 in a 60-min test of absorption enabling safe, simple and repeated measurements in renal failure patients.