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High rates of variation in HLA-DQ2/DQ8 testing for coeliac disease: results from an RCPAQAP pilot program
  1. Martin Patrick Horan1,
  2. Sze Yee Chai1,
  3. Nalishia Munusamy1,
  4. Kwang Hong Tay1,
  5. Louise Wienholt1,
  6. Jason A Tye-Din2,3,
  7. James Daveson4,5,6,
  8. Michael Varney7,
  9. Tony Badrick1
  1. 1 RCPAQAP Molecular Genetics, St. Leonard’s, Sydney, New South Wales, Australia
  2. 2 Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
  3. 3 Gastroenterology Department, The Royal Melbourne Hospital, Parkville, Victoria, Australia
  4. 4 University of Queensland, Brisbane, Queensland, Australia
  5. 5 Wesley Medical Research, Brisbane, Queensland, Australia
  6. 6 St Andrew’s War Memorial Hospital, Brisbane, Queensland, Australia
  7. 7 Victorian Transplantation and Immunogenetics Service, Australian Red Cross Blood Service, Melbourne, Victoria, Australia
  1. Correspondence to Dr Martin Patrick Horan, RCPAQAP Molecular Genetics, St. Leonard’s, Sydney, NSW 2065, Australia; martin.horan{at}rcpaqap.com.au

Abstract

Aim Coeliac disease(CD) is a highly prevalent, gluten-dependent, autoimmune enteropathy. While the diagnosis is based on serological and histological criteria, genotyping of the human leucocyte antigens (HLA) DQ2 and DQ8 has been shown to have substantial clinical utility, especially in excluding the diagnosis in patients who do not carry either antigen. As a result, HLA genotyping is now being performed by more laboratories and has recently become one of the most frequently requested genetic tests in Australia. To date, there has been little scrutiny on the accuracy and reporting of results by laboratories new to HLA typing. In response to clinician feedback that identified potentially clinically significant discrepancies in HLA typing results, the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) undertook a pilot study to assess laboratory performance in the detection of HLA-DQ2/DQ8 and their associated HLA-DQA1 and HLA-DQB1 alleles.

Methods DNA was extracted from 5 patients and sent to 10 laboratories for external quality assurance (EQA) testing. Laboratories were assessed for reporting in genotyping, interpretation and methodology.

Results Our findings showed that at least 80% of laboratories underperform with respect to recommended guidelines for HLA typing and reporting for CD, with 40% of laboratories failing to provide any clinical interpretation or full genotyping data. This suboptimal level of reporting may lead to ambiguities for downstream clinical interpretation that may compromise patient management.

Conclusions These findings highlight the importance of adherence to standardised guidelines for optimal performance and reporting of HLA results and substantiate the need for EQA and proficiency testing for laboratories providing this service.

  • coeliac disease
  • quality assurance
  • HLA

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Footnotes

  • Handling editor Runjan Chetty.

  • Contributors MPH, SYC, NM, LW, JAT-D, JD, MV and TB designed the study, analysed the data, drafted and revised the manuscript. KHT performed the experiments, analysed the data and revised the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests JAT-D is a coinventor of patents pertaining to the use gluten peptides in therapeutics, diagnostics and non-toxic gluten in coeliac disease. He is a shareholder of Nexpep Pty Ltd and a consultant to ImmusanT Inc. Nexpep Pty Ltd and ImmusanT Inc. were formed to develop novel diagnostics and treatments for coeliac disease. This work was designed, developed, prepared and funded by the RCPAQAP. Other authors have no competing interests to declare.

  • Patient consent Not required.

  • Ethics approval RCPA Quality Assurance Programs Pty Limited.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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