title: Chemical and morphological analysis of kidney stones: a double-blind comparative study.
abstract: 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.
authors.affiliation: Federal University of Rio Grande do Norte, Natal, Brazil.
authors.forename: Silvia Fernandes Ribeiro da
authors.initials: SF
authors.lastname: Silva
authors.forename: Djamile Cordeiro de
authors.initials: DC
authors.lastname: Matos
authors.forename: Sônia Leite da
authors.initials: SL
authors.lastname: Silva
authors.forename: Elizabeth De Francesco
authors.initials: Ede F
authors.lastname: Daher
authors.forename: Henry de Holanda
authors.initials: Hde H
authors.lastname: Campos
authors.forename: Carlos Antonio Bruno da
authors.initials: CA
authors.lastname: Silva
mesh_terms: 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