Recruitment of study group will be through the Urology and Stone Clinic in the Diamond Health Care Centre at Vancouver General Hospital and Dr Joel Teichman's Practice at St Paul's Hospitals. Patients will be asked to participate by a urologist (Drs Chew, Teichman, Nigro, Fenster or Paterson) or the research coordinator. Control patients will be matched for age and sex to the study group. They will have no history of stone disease. The consent form will be provided to the participants by one of the investigators or a clinical research coordinator involved in the study. This will occur in one of the urology clinics.