The study of the crystalluria is the search and the identification for crystals in urines. This multi-parametric study brings a precious help in the diagnosis and/or the follow-up of acquired or congenital lithiasis. The lack of the internal urinary quality control (IQC) makes the accreditation of this analysis, according to the NF EN ISO 15189 standard, particularly delicate. After a presentation of the three steps (pre-analytical, analytical and post-analytical) performed in the laboratory, the authors present some insights in order to mitigate the lack of the urinary IQC. These insights, particularly concern by the "misappropriation" of IQC, the elaboration of an "in house" IQC as well as by the evaluation of the external evaluation of the quality. Thanks to the implementation of these tools, it becomes easier to prove that the laboratory of medical biology masters the qualification, the authorization and the continuous preservation of the skills of the operators performing the study of the crystalluria.
Keywords: ISO 15189; crystalluria; quality control.