title: Fiberoptic infrared spectroscopy: a novel tool for the analysis of urine and urinary salts in situ and in real time.
abstract: OBJECTIVE
  To use infrared fiberoptic spectroscopy for the analysis of urinary salts in real time and with no sample processing; and to assess the practical role of this method for the quantitative measurement of the composition of urine and for the diagnosis of urolithiasis in patients.
  
  
  METHODS
  Urine samples were obtained from two groups of patients: 24 patients with stone formation after shock wave lithotripsy and 24 normal subjects of similar age. Infrared absorption measurements were performed in real time, using infrared transmitting silver halide fibers. The absorption data were compared with the infrared absorption spectra of aqueous solutions prepared in our laboratory, with known concentrations of known urinary salts. The results were used for the study of the chemical composition of these salts in the urine samples and for a quantitative analysis of the concentration of the salts.
  
  
  RESULTS
  We determined the composition of the stones in 20 of the 24 patients on the basis of the characteristic absorption peaks for the oxalates, carbonates, urates, and phosphates observed in their urinary samples. Using the method mentioned above, we found the concentration of different salts in urine with an average error of 20%.
  
  
  CONCLUSIONS
  Fiberoptic infrared spectroscopy could be used as a new diagnostic tool for detecting different urinary salts in urine, finding their chemical composition, and determining their concentrations, without any sample preparation.
authors.affiliation: Department of Urology, Barzilai Medical Center, Ashkelon, Israel.
authors.forename: Shmuel
authors.initials: S
authors.lastname: Cytron
authors.forename: Sergey
authors.initials: S
authors.lastname: Kravchick
authors.forename: Ben-Ami
authors.initials: BA
authors.lastname: Sela
authors.forename: Evgeny
authors.initials: E
authors.lastname: Shulzinger
authors.forename: Irena
authors.initials: I
authors.lastname: Vasserman
authors.forename: Yosef
authors.initials: Y
authors.lastname: Raichlin
authors.forename: Abraham
authors.initials: A
authors.lastname: Katzir
mesh_terms: D002254:Carbonates / Q000652:urine; D005336:Fiber Optic Technology / Q000379:methods*; D006801:Humans; D008096:Lithotripsy; D010070:Oxalates / Q000652:urine; D012492:Salts / Q000032:analysis / Q000652:urine*; D013055:Spectrophotometry, Infrared / Q000379:methods*; D014527:Uric Acid / Q000652:urine; D014545:Urinary Calculi / Q000175:diagnosis / Q000628:therapy / Q000652:urine*; D014556:Urine / Q000737:chemistry*
chemical_list: D002254:Carbonates; D010070:Oxalates; D012492:Salts; D014527:Uric Acid