[Analysis of the composition of 2700 urinary calculi examined by infrared spectrophotometry, 1979-1989]

Two thousand seven hundred samples, received as urinary calculi, in a Turin based laboratory, in the period between March 1979 and February 1989, were examined by infrared spectroscopy to identify components even of difficult characterization: a special procedure was used and it is described. Knowing the composition of each calculus, a comparison was made between the incidence of each compound in the first 1500 samples (1979-1984) and in the remaining 1200 ones (1984-1989). Besides an increase in calcium oxalate as main component, a marked reduction in incidence of struvite was found in the calculi belonging to the second period of observation. The possible interference in calculi composition by various therapy for renal infection is discussed.