Inherited metabolic disorders: Quality management for laboratory diagnosis

The advancements in laboratory technology and knowledge of the mechanisms behind metabolic disorders have facilitated accurate and reliable laboratory testing in screening, diagnosis and treatment of inherited metabolic disorders. Therefore, quality assurance and improvement in diagnostic proficiency have become essential in this area. In most developing countries, standard practices for quality assurance in testing of enzymes, hormones and metabolites involved in these genetic disorders have not been fully implemented. We highlight the benefits of quality assurance and aim to create awareness for greater compliance with the criteria established for quality control to ensure accuracy in biochemical genetic testing.

Establishing the limit of detection and testing range for each analyte and enzyme are useful as a reference while setting up new assays. To minimize error, %CV should be monitored regularly. Evaluation of proficiency testing performance provides scope to the laboratory for improving testing quality.

Low precision seen in lysosomal enzyme assays does not undermine their diagnostic efficacy as differentiation between patients and normal subjects is possible by setting % coefficient of variation cutoffs.

The study will facilitate the collaboration with other screening and diagnostic systems and help in development of new laboratory standards.