The project aims to produce and certify the reference material (CRM) and the low and high level of quality control materials to be used in newborn screening tests and routine clinical measurements of amino and organic acids in plasma and urine samples. In order to obtain reliable results from the kits and instruments used for the determination of amino and organic acids, system calibration and quality control procedures must be conducted for which certified reference materials (CRMs) are required. Particularly, it is important to use CRMs having the same chemical compositions (matrix matched CRM) as the samples for the detection of subject quantity in the mixtures (matrix), such as body fluids, containing more than one metabolite. The use of CRMs in measurements ensures the metrological traceability chain. TUBITAK UME's quality management system has been organized to cover the production of CRM and has been internationally peer reviewed. Production and certification processes, based on ISO Guide 34 and Guide 35, are realized in accordance with a series of pre-determined requirements. Reference material production process comprises the following sub-steps: preliminary studies, material processing, homogeneity and short and long-term stability tests, characterization, certification and certification follow up.