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


CONCLUSIONS
We suggest kidney stones be routinely submitted to both types of analysis for a better understanding of the mechanisms involved in lithogenesis.
Silva
Silvia Fernandes Ribeiro da
SF
Federal University of Rio Grande do Norte, Natal, Brazil.
Matos
Djamile Cordeiro de
DC
Silva
Sônia Leite da
SL
Daher
Elizabeth De Francesco
Ede F
Campos
Henry de Holanda
Hde H
Silva
Carlos Antonio Bruno da
CA
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D055815:Young Adult