10,000 analyses of urinary calculi using X-ray diffraction and polarizing microscopy.

To make qualitative as well as semiquantitative analyses of 10,000 urinary calculi of large city population, a combined crystal-optical X-ray diffractometric method proved to be very useful. This combination goes to complement the advantages of polarization microscopy (with its minimal substance requirements, its proof limits of less than 1%, and its insight into stone texture) with those of X-ray diffraction (with its fast semiquantitative analysis and simple differentiation of all the stone components). About 30% of the calculi were found to have a monomineral composition. The most frequent types of calculi in our examination were: 33.2% whewellite/weddellite, 24.9% whewellite, 13.5% whewellite/weddellite/apatite, 7.0% struvite/apatite, and 3.9% uric acid/uric acid dihydrate.