The composition and quantitative analysis of urinary calculi in patients with renal calculi.

To get complete information about the chemical composition and physicochemical principles underlying the formation of stone there is a need for more precise information. At present there is no single analytical procedure that provides an exact quantitative analysis of urinary calculi. In this present procedure it is assumed that only calcium oxalate monohydrate, hydroxyapatite, or magnesium ammonium phosphate hexahydrate are present in stone, therefore the percent chemical composition of stone is calculated on the basis of molecular weight of an element and related molecular formula of the stone. By analysis of 100 stones the chemical composition observed with Mean +/- SD value for calcium is 25.68 +/- 5.38, for Calcium oxalate hydrate crystal is 32.84 +/- 17.28 which contains oxalic acid 20.35 +/- 10.70, for Apatite crystal is found to be 41.70 +/- 16.56 which contains inorganic phosphate 8.09 +/- 3.08. Total uric acid found in these stones is 27.12 +/- 11.42. Major component are calcium oxalate 32.8% (combined monohydrate and dihydrate), Phosphate 41.7%, Magnesium ammonium phosphate hexahydrate 3.3% and uric acid 27.1%. No pure stone was obtained. Calcium oxalate was present in nearly all stones, and the majority of renal calcium stones contains mixtures of calcium oxalate and calcium phosphates in addition some contains uric acid or magnesium ammonium phosphate. The mixture of calcium oxalate/uric acid/magnesium ammonium phosphate hexa hydrate has never been observed.