Analytical and clinical studies of oxalate in stone formers

The metabolic processes involved in the production of oxalate from its major precursors were reviewed, and the analytical techniques used for the analysis of oxalate in biological material examined. An automated enzymic procedure for urinary oxalate utilising oxalate decarboxylase and formate dehydrogenase was developed and evaluated using the reference method. The chosen procedure was subsequently employed for the determination of oxalate in urine obtained from a group of volunteers free of a history of stone formation and other disorders. A wide variation of oxalate excretion both within and between individuals was noted. The reference procedure was used for urine oxalate analyses of 24 hour collections from 3 groups of stone formers ascribed one of two therapies; allopurinol or bendrofluazide. Biochemical tests of serum (calcium, magnesium, zinc and urate concentrations) and urine (calcium, magnesium creatinine and urate excretion) were also undertaken