One hundred thirty-seven urinary calculi were analyzed by means of X-ray, diffraction, ultraviolet spectroscopy and chemical method.
1. The most frequently found constituent in these 137 calculi was calcium oxalate that was found in 101 calculi (76.0% of the series). Of these 104 calculi pure calcium oxalate was identified in 41, of which 14 (10.2%) were composed of pure monohydrate and 27(19.7%) were mixtures of monohydrate and dihydrate.
The dihydrates were only found to be mixed with monohydrates and the two hydrates could be identified only by X-ray diffraction but not by chemical method.
2. Identification of phosphate by X-ray diffraction was difficult because of its low peak intensity, while chemical method was proved to be more sensitive and accurate for phosphate.
Calcium phosphate was found not in the pure state but in the: mixed form with calcium oxalate in 39 calculi (28.5%).
3. Pure uric acid constituent was very rare, being oily found in 2 calculi (1.5%). But there were 41 calculi (29.9%) mixed with a minute amount of uric acid, of which 28 (68.3%) were associated with calcium oxalate monohydrate.
Only one calculus of uric acid, which did not appear to be crystallized, was detected by ultraviolet spectroscopy.
4. There were 23 calculi (16.8%) of magnesium ammonium phosphate, of which 13 (56.5%) were mixed with calcium phosphate and only 3 (13. 0%) were found to be in the pure state.
5. Xanthine was found as a minor constituent in t calculi, all coexistent with uric acid. There was no calculus of cystine detected.
6. X-ray diffraction method bad the advantages of providing a permanent record and a semiquantitative result and of identifying minute components. However it was unsatisfactory for detecting phosphate constituent.
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