[Ensuring quality in the analyses of urinary calculi by a comparison of methods. 3d International Ring Trial].

Of 5 analysis tests of the 3rd International Ring Experiment for the control of the quality of methods of the analysis of urinary calculi 38 findings compiled according to 9 different techniques came in from 12 countries. The average deviation per component concerning all 5 analysis tests is considerably low with 0.10 mol proportions. The average quality measure SQ concerning all participants is approximately 2.00; it deteriorates from the X-ray diffraction method over the IR-technique to the other quantitative methods used. Advantages and disadvantages of the X-ray diffraction and IR-spectroscopic analysis are discussed. A methodically homogeneous and centralized performed analysis of urinary calculi shows advantages in the quality of the analyses.