[Study of spontaneous crystalluria using infrared spectroscopy. Research on correlations between crystals, calculi, bacteria and the sex of the patients].

6 100 specimens of urine were examined according to classical cytobacteriological techniques for the presence of crystals and the possible correlations with the bacteria identified and the sex of the patients. When crystals were present, the urine was centrifuged and the deposit was dried in a filter with low porosity, scraped away and incorporated in a tablet of potassium bromide and then examined by infra-red spectrophotometry. Positive crystalluria was found in 6.4% of urines from patients without lithiasis and in 59% of cases with lithiasis. Only 50% of cases had a pure mineral type. Struvite was the most common (34.3%), then weddellite (33.1%), carbapatite (23.1%), amorphous calcium phosphate (22.7%) and ammonium urate (18.3%). Any of these compounds could be found pure or in combination with others. The other constituents were appreciably less common. All in all, 76 types of crystalluria were demonstrated. Important differences in crystallurias and the bacteria identified were detected as a function of the sex of the patients. Positive correlations were found between a number of bacteria and the crystals with which they are associated. The distribution and the composition of the cases of crystalluria were compared with those of urinary calculi.