Application of LIIR Automatic Analysis System of Infrared Spectroscopy in the determination of urinary stone composition / 中华泌尿外科杂志

ABSTRACT

Objective To determine the value of applying LIIR Automatic Analysis System of Infrared Spectroscopy in analyzing urinary stone composition. Methods 1450 samples of urinary stones were collected from 1032 male and 418 female patients. The age of patients ranged from 6 months to 88 years. The mean ages were 41.7±15.3 and 42.0±15.6 years for male and female patients, respectively. Of 1450 stones, 875 cases were located in kidney (60.34%), 504 cases in ureter (34.76%) and 71 cases in bladder (4.90%). All stones were analyzed by LIIR Automatic Analysis System of Infrared Spectroscopy (Tianjin). Analysis results were reevaluated by the artificial analysis of spectrogram, if necessary, with polarization microscope, chemical analysis, and X-ray diffraction.Results Calcium oxalate monohydrate stones were found in 714 cases (49. 24%), carbonate apatite stones in 444 cases (30.62%), anhydrous uric acid stones in 93 cases (6.41%), calcium oxalate dihydrate stones in 92 cases (6. 34 % ), ammonium magnesium phosphate hexahydrate stones in 28 cases (1.93%), cystine stones in 23 cases (1.59%), ammonium urate stones in 20 cases (1.38%), uric acid dihydrate stones in 16 cases (1.10%), brushite stones in 12 cases (0.83%), sodium urate monohydrate stones in 2 cases (0. 14%), calcium carbonate stones in 1 cases (0. 07%), and other stone types in 5 cases (0. 34%). Most urinary stones were composed of 2 or more compositions, and pure stones were only observed in 397 cases (27.38%). Most of the mixed stones contained calcium and non-calcium mixed stone was rarely observed. In addition, 15 stones were found in infants who had consumed melamine-contaminated milk powder. These stones were composed of uric acid dihydrate and ammonium urate. The results of reevaluation by artificial analysis showed the following among pure and mixed stones, false detection occurred in 6 cases (0.41%), of which the composition was ammonium urate or carbonate apatite determined by automatic system but the true composition was anhydrous uric acid. False negative detection occurred in 9 cases (0.62%), of which the composition was ammonium magnesium phosphate hexahydrate or carbonate apatite in 7 cases, but in other 2 cases the composition could not be determined by artificial analysis. The false negative detection of components with relatively low content occurred in 6 cases and 10 cases in stones with 2 components and 3 components, respectively. The undetected composition in these cases was ammonium magnesium phosphate hexahydrate or carbonate apatite. Conclusion Automatic Analysis System of Infrared Spectroscopy has many advantages in accuracy, automation and is quick in analyzing the composition of urinary stones, and is worthy of promotion in clinical use.