[Carefully conducted preanalytic and postanalytic procedures for urine samples. Often neglected in urolithiasis treatment].

Particularly in the urological consultation sessions collection of 24 h urine samples is required to evaluate the metabolic risk factors for urolith formation. To ensure a yield from urinalysis of sufficiently high quality and to minimize the number of potential error sources, correctly performed preanalytical procedures are required. If certain basic quality criteria for the collection procedures are not being followed false data can be determined and the clinical interpretation based on that analysis will result in a wrong rating of the true metabolic status of patients. This article provides practical, feasible and proven solutions in an encouraging, motivating and clear way to ensure that at least the most important steps for a correct urine collection are being taken. The preanalytical requirements for the determination of other urinary parameters which are not in the direct focus of urolithiasis treatment will not be covered by this article.