[Methodologic comparison of the analysis of urinary calculi. Roentgen diffractometry, polarization microscopy and...

Not only instrumental, apparative or operative stone extraction is necessary for patients with urolithiasis (particularly those with recurrent urolithiasis); preventive treatment is also called for, and for this exact analysis of the composition of the stones is essential. The procedures currently accepted as standard for stone analysis are: X-ray diffraction, infrared spectroscopy, polarisation microscopy and the complicated chemico-quantitative analyses performed in some institutes. Recently a new, so-called microscopic-microchemical, analysis of stone components has been presented (the Harzalith). To test the value of this procedure as compared to e.g. X-ray diffraction or polarization microscopy, a comparative study was carried out in our department. Thirty different urolith compositions (calculi with one and with more components) were analysed qualitatively and quantitatively by three methods. No qualitative difference was found between X-ray diffraction and polarization microscopy; however, there was a difference from the Harzalith method, and with increasing number of components there was hardly any correspondence with the other methods. Only 10% of the calculi with three or four components could be analysed correctly. Often, too many components were determined by the new method. The test material was analysed by three laboratory assistants working independently of each other.