Proficiency testing in a biochemical genetics laboratory

Introduction: Diagnosis of Inborn errors of metabolism (IEMs) has grown out from academic laboratories to formal clinical settings. However owing to the rare nature of IEMs, laboratories might not encounter all the tested disorders even over decades of service. In such cases proficiency testing (PT) programs offer an opportunity to assure an expertise. Our laboratory has enrolled for amino acid & Urinary Glycosaminoglycan (GAG) estimation and Congenital Disorders of Glycosylation (CDG) diagnosis PT program from European Research Network for evaluation and improvement of screening, Diagnosis and treatment of Inherited disorders of Metabolism (ERNDIM) since January 2015. Aims and Objectives: To review PT cycle performance & implement measures to improve laboratory competence. Materials and Methods: In the beginning of the year lyophilized samples (8 for amino acids and 6 each for CDG & GAGs) were received. Amino acid samples were to be reported each at 6-7 weeks interval while CDG & GAGs at 6 months interval in a batch of 3 each. Clinical history for GAG & CDGs was provided for interpretation and suggestions for further clinical workup. Timely evaluation report was received to ensure corrective measures. Results: Subsequent to the systemic bias obtained for amino acids our HPLC method was modified to offer a comprehensive physiological amino acid panel. The clinical history correlation of GAG & CDG samples coached us to interpret rare phenotypes of these diseases. Conclusion: Participation in PT programs is essential and beneficial for quality assurance & training of laboratory personnel offering IEM diagnosis.