title: Laser-induced breakdown spectroscopy is a reliable method for urinary stone analysis.
abstract: OBJECTIVE
  We compared laser-induced breakdown spectroscopy (LIBS) with the traditionally used and recommended X-ray diffraction technique (XRD) for urinary stone analysis.
  
  
  METHODS
  In total, 65 patients with urinary calculi were enrolled in this prospective study. Stones were obtained after surgical or extracorporeal shockwave lithotripsy procedures. All stones were divided into two equal pieces. One sample was analyzed by XRD and the other by LIBS. The results were compared by the kappa (κ) and Spearman's correlation coefficient (rho) tests.
  
  
  RESULTS
  Using LIBS, 95 components were identified from 65 stones, while XRD identified 88 components. LIBS identified 40 stones with a single pure component, 20 stones with two different components, and 5 stones with three components. XRD demonstrated 42 stones with a single component, 22 stones with two different components, and only 1 stone with three different components. There was a strong relationship in the detection of stone types between LIBS and XRD for stones components (Spearman rho, 0.866; p<0.001). There was excellent agreement between the two techniques among 38 patients with pure stones (κ index, 0.910; Spearman rho, 0.916; p<0.001).
  
  
  CONCLUSIONS
  Our study indicates that LIBS is a valid and reliable technique for determining urinary stone composition. Moreover, it is a simple, low-cost, and nondestructive technique. LIBS can be safely used in routine daily practice if our results are supported by studies with larger numbers of patients.
authors.affiliation: Department of Urology, Kocaeli University School of Medicine, Kocaeli, Turkey.
authors.forename: Nazım
authors.initials: N
authors.lastname: Mutlu
authors.affiliation: Clinic of Urology, Sivas Numune Hospital, Sivas, Turkey.
authors.forename: Seyfettin
authors.initials: S
authors.lastname: Çiftçi
authors.affiliation: Clinic of Urology, Hakkari State Hospital, Hakkari, Turkey.
authors.forename: Turgay
authors.initials: T
authors.lastname: Gülecen
authors.affiliation: Laser Technologies Research and Application Center, Kocaeli University, Kocaeli, Turkey.
authors.forename: Belgin Genç
authors.initials: BG
authors.lastname: Öztoprak
authors.affiliation: Laser Technologies Research and Application Center, Kocaeli University, Kocaeli, Turkey.
authors.forename: Arif
authors.initials: A
authors.lastname: Demir
keywords: Laser spectroscopy; X-ray diffraction; stone analysis; urinary calculi