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

Silvia Fernandes Ribeiro Da Silva,Sônia Leite Da Silva,Djamile Cordeiro De Matos,Elizabeth De Francesco Daher,Carlos Antonio Bruno Da Silva,Henry De Holanda Campos

doi:10.1590/s0102-86502010000500011

Silvia Fernandes Ribeiro Da Silva, Sônia Leite Da Silva + Show 4 more

Open Access

https://doi.org/10.1590/s0102-86502010000500011

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Abstract

To compare chemical to morphological kidney stone composition analysis based on a sample of 50 stones retrieved from patients at a nephrology service. 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). 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. We suggest kidney stones be routinely submitted to both types of analysis for a better understanding of the mechanisms involved in lithogenesis.

Highlights

Urinary lithiasis is a common condition currently affecting 4–20% of the world population[1,2]
The objective of the present study was to compare chemical to morphological kidney stone composition analysis based on a sample of 50 stones retrieved from patients at a nephrology service
This was a cross-sectional, double-blind study comparing chemical to morphological kidney stone composition analysis based on a sample of 50 stones retrieved from patients referred to the Crystalluria Research Laboratory, Center for Hepatic and Renal Diseases - a division of the Federal University of Ceara (Fortaleza, Brazil)

Summary

Introduction

Urinary lithiasis is a common condition currently affecting 4–20% of the world population[1,2]. The risk of a normal adult developing lithiasis ranges from low to high: 1–5% in Asia, 5–9% in Europe, 13% in the US and 20.1% in Saudi Arabia[3]. In Brazil, 5–10% of the population suffers from urinary lithiasis. The main related metabolic changes observed are hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia and hypomagnesiuria[4,5,6]. These metabolic disorders are risk factors for lithiasis, but may occur in patients who never develop kidney stones. The best indicator–and only gross evidence–of lithiasis is kidney stones formed in the urinary system[7,8]

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