Nowadays there is still a debate which patient requires metabolic evaluation. One helpful consideration could be the stratification of patient to low and high risk of recurrence. For routine every day practice abbreviated protocol for low-risk single stone formers may be applied in stone formers evaluated without increases risk of recurrence [2, 3] (Table 24.2). A comprehensive evaluation is mandatory in patient who present with episodes of recurrence and are evaluated as stone formers at high risk. Historically extensive metabolic evaluation included fast and calcium loaded tests in order to discriminate between various forms of hyperoxaluria. In every day setting routine performance of calcium fast/load test is not required t complete metabolic evaluation (Table 24.3). Most urologists would perform specific metabolic evaluation of collection of two consecutive 24-h urine samples [4, 7]. For the initial specific metabolic work-up, the patient should stay on a self-determined diet under the conditions of everyday lifestyle. Follow-up should be performed at 6–12 weeks after the initiation of treatment regimen for stone recurrence.