title: Not water, but formalin, dissolves urate crystals in tophaceous tissue samples.
abstract: OBJECTIVE
  To examine the relative solubility of urate crystals in water, formalin, and ethanol.
  
  
  METHODS
  Weighed aliquots of synthetic crystals were incubated in each solvent for 72 h at 4 degrees C and were then examined by polarized microscopy.
  
  
  RESULTS
  urate crystals were insoluble in alcohol, sparingly soluble in water, and markedly soluble in formalin.
  
  
  CONCLUSIONS
  The marked solubility of urate in formalin is consistent with formation of urate:formaldehyde addition products.
authors.affiliation: Department of Medicine, University of Washington, Seattle 98195.
authors.forename: P A
authors.initials: PA
authors.lastname: Simkin
authors.forename: J E
authors.initials: JE
authors.lastname: Bassett
authors.forename: Q P
authors.initials: QP
authors.lastname: Lee
mesh_terms: D003460:Crystallization; D000431:Ethanol / Q000737:chemistry; D005557:Formaldehyde / Q000737:chemistry*; D006073:Gout / Q000473:pathology; D006801:Humans; D012995:Solubility; D014527:Uric Acid / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D005557:Formaldehyde; D014527:Uric Acid; D000431:Ethanol