title: Inherited metabolic disorders: Quality management for laboratory diagnosis.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  The study will facilitate the collaboration with other screening and diagnostic systems and help in development of new laboratory standards.
authors.affiliation: Centre of Medical Genetics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India. Electronic address: j4verma@yahoo.com.
authors.forename: Jyotsna
authors.initials: J
authors.lastname: Verma
authors.affiliation: Centre of Medical Genetics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India.
authors.forename: Divya C
authors.initials: DC
authors.lastname: Thomas
authors.affiliation: Centre of Medical Genetics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India.
authors.forename: Sandeepika
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Centre of Medical Genetics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India.
authors.forename: Geetu
authors.initials: G
authors.lastname: Jhingan
authors.affiliation: Centre of Medical Genetics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India.
authors.forename: Azad
authors.initials: A
authors.lastname: Singh
authors.affiliation: Preventive Medicine Foundation, Taipei, Taiwan.
authors.forename: Kwang-Jen
authors.initials: KJ
authors.lastname: Hsiao
authors.affiliation: Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Kees
authors.initials: K
authors.lastname: Schoonderwoerd
authors.affiliation: Centre of Medical Genetics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India.
authors.forename: Ratna D
authors.initials: RD
authors.lastname: Puri
authors.affiliation: Centre of Medical Genetics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India.
authors.forename: Ishwar C
authors.initials: IC
authors.lastname: Verma
mesh_terms: D019411:Clinical Laboratory Techniques / Q000592:standards*; D059788:Dried Blood Spot Testing; D006801:Humans; D007231:Infant, Newborn; D057230:Limit of Detection; D008247:Lysosomes / Q000201:enzymology; D008659:Metabolic Diseases / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics*; D011785:Quality Assurance, Health Care / Q000379:methods*
keywords: Diagnostic proficiency; Inherited metabolic disorders; Lysosomal enzymes; Quality control procedures; Succinyl acetone