Chemical and morphological analysis of kidney stones: a double-blind comparative study

Análise química e morfológica de cálculos renais: estudo comparativo duplo-cego

Silvia Fernandes Ribeiro da Silva Djamile Cordeiro de Matos Sônia Leite da Silva Elizabeth De Francesco Daher Henry de Holanda Campos Carlos Antonio Bruno da Silva About the authors

PURPOSE: To compare chemical to morphological kidney stone composition analysis based on a sample of 50 stones retrieved from patients at a nephrology service. METHODS: The chemical analysis was performed with a Bioclin® kit, while a 10-mm magnifying glass (10x; Prolabo, Paris, France) was employed in the morphological analysis. Findings obtained with the two methods were compared and classified as concordant (100% agreement), partly concordant (concordant for major components, discordant for minor components) or discordant (discordant for major components). RESULTS: In the chemical analysis, the most commonly observed major component was calcium (70%), followed by oxalate (66%), ammonium (56%), urate (28%) and carbonate (24%). In the morphological analysis, the most commonly observed major components were calcium phosphate and magnesium (32% each), followed by calcium oxalate monohydrate (24%), uric acid and urates (20% each), calcium oxalate dihydrate (18%) and cystine (6%). Infectious kidney stones were identified in 34% and 24% of cases by morphological and chemical analysis, respectively. Thirty-eight percent of the samples were classified as concordant, 52% were partly concordant and 10% were discordant. CONCLUSION: We suggest kidney stones be routinely submitted to both types of analysis for a better understanding of the mechanisms involved in lithogenesis.

Morphology; Urinary Calculi; Urinary Bladder Calculi


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