[Urinary calculi analysis using X-ray diffraction: selection, use and advantages].

Analysis of urinary calculi by X-ray diffraction: The evaluation of X-ray diffraction for the analysis of urinary calculi led to the substitution of the analysis by qualitative-chemical reactions. This instrumental method is performed in the routine laboratory in Zurich since two years. The interlaboratory quality assurance programme of 100 laboratories showed the advantage of the new method, producing correct results. On the contrary the old fashioned method by qualitative-chemical reactions yields questionable results.