Different types of hypercalciuria in patients with renal lithiasis and evidence of the calcium renal waste.

A study of normal subjects and patients with hypercalciuria and recurrent renal stones has identified three main types of hypercalciuria: complex, absorptive and renal. Complex hypercalciuria is a combination of absorption, renal leak and resorption factors. Absorption and renal leak were examined by means of a 45Ca test. Resorption is defined as an increase of the urinary calcium:creatinine ratio while the subjects are being maintained on an intake of 400 mg of calcium per 24 h.