Poster Presentation International Association of the Diabetes and Pregnancy Study Groups 2022 - Hosted by ADIPS

Oral glucose tolerance test to diagnose gestational diabetes mellitus: impact of variations in specimen handling (#105)

Emma L Jamieson 1 , Goce Dimeski 2 3 , Robert Flatman 4 , Peter E Hickman 5 , Graham RD Jones 6 7 , Julia V Marley 8 , David McIntyre 9 , Alan R McNeil 10 , Christopher J Nolan 11 12 , Julia M Potter 13 , Arianne Sweeting 14 15 , Peter Ward 16 , Paul Williams 17 , Andrea Rita Horvath 18
  1. The Rural Clinical School of Western Australia, The University of Western Australia, Bunbury, WA, Australia
  2. Pathology QLD, Chemical Pathology, Princess Alexandra Hospital, Wooloongabba, QLD, Australia
  3. Faculty of Medicine, The University of Queensland, Herston, QLD, Australia
  4. Sullivan Nicolaides Pathology, Bowen Hills, QLD, Australia
  5. ACT Pathology, Garran, ACT, Australia
  6. Department of Chemical Pathology, SydPath, Darlinghurst, NSW, Australia
  7. School of Clinical Medicine, Faculty of Medicine and Health, The University of New South Wales, Kensington, NSW, Australia
  8. The Rural Clinical School of Western Australia, The University of Western Australia, Broome, WA, Australia
  9. Mater Research, The University of Queensland, South Brisbane, QLD, Australia
  10. Dorevitch Pathology, Heidelberg, VIC, Australia
  11. Australian National University Medical School, The Australian National University, Acton, ACT, Australia
  12. Department of Endocrinology, The Canberra Hospital, Garran, ACT, Australia
  13. Australian National University Medical School, The Australian National University, Acton, ACT, Australia
  14. Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
  15. Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
  16. NSW Health Pathology, Department of Chemical Pathology, St Leonards, NSW, Australia
  17. Greg Brown Department of Endocrinology, The University of Sydney, Sydney, NSW, Australia
  18. NSW Health Pathology, Department of Chemical Pathology, Randwick, NSW, Australia

Acknowledgements

The authors acknowledge the support of the Australasian Association for Clinical Biochemistry and Laboratory Medicine (AACB) and the Royal College of Pathologists of Australasia (RCPA). This abstract reflects the views of the authors who are members of the AACB-RCPA Harmonisation Glucose Preanalytical Working Group. 

Aim

To conduct a narrative review of contemporary approaches to minimise preanalytical glycolysis in oral glucose tolerance test (OGTT) samples with a focus on GDM diagnosis using criteria derived from the Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study. The challenges of implementing each approach across a diverse Australian healthcare setting were explored.

Results

Many Australian sites currently collect and transport OGTT samples at ambient temperature in sodium fluoride (NaF) tubes which likely leads to missed diagnosis of GDM in a significant proportion of cases. Alternative preanalytical solutions should be pragmatic and tailored to individual settings and as close as possible to the preanalytical conditions of the HAPO study for correct interpretation of OGTT results.

Rapid centrifugation of barrier tubes to separate plasma could be suitable in urban settings provided time to centrifugation is strictly controlled (estimated 1.8-fold increase in GDM). Tubes containing NaF and citrate could be useful for remote or resource poor settings with long delays to analysis but the impact on the interpretation of OGTT results should be carefully considered (estimated 1.4- to 4.2-fold increase in GDM). Testing venous blood glucose at the point-of-care bypasses the need for glycolytic inhibition but requires careful selection of devices with robust analytical performance (estimated impact on GDM not reported).

Conclusions

Studies to evaluate the potential error of each solution compared to the HAPO protocol are required to assess the magnitude of misdiagnosis and inform clinicians regarding the potential impact on patient safety and healthcare costs.