At the International Kidney Stone Institute, our goal is nothing less than the cure.

Calcium Stones


Nearly 80 percent of all kidney stones are composed of calcium and oxalate.  Stones composed of calcium and phosphate are also common.  At least half of the people with calcium stones have abnormally high levels of calcium in the urine, a condition called hypercalciuria.  This condition can occur due to increased absorption of dietary calcium in the intestine, loss of calcium from bones, or problems with how the kidneys normally control the amount of calcium in the urine. Dietary, metabolic and genetic factors can be involved in producing excess amounts of urinary calcium.  For example, calcium stones often form in those suffering from overactivity of the parathyroid glands that regulate the body’s calcium balance (by releasing parathyroid hormone).  Calcium oxalate stones can also form due to excess amounts of oxalate in the urine.  This is most commonly discovered in people with a history of inflammatory disease or surgery of the intestinal tract.  Rarely, calcium phosphate stones can result from a condition called renal tubular acidosis, where the kidney is unable to appropriately acidify the urine.