title: Glycosylated haemoglobin for screening and diagnosis of gestational diabetes mellitus.
abstract: OBJECTIVE
  The oral glucose tolerance test (OGTT) is a cumbersome test that is time consuming, labour intensive and often poorly tolerated by pregnant women. To date, glycosylated haemoglobin (HbA1c) is the most accepted measure of chronic glycaemia outside of pregnancy. HbA1c is an uncomplicated test, less time consuming, does not require any specific patient preparation and is considered straightforward compared with the OGTT. Therefore, we prospectively tested the utility of the HbA1c when used as a screening tool in pregnancy for gestational diabetes mellitus (GDM).
  
  
  METHODS
  Primary health care. Single tertiary referral centre, Tasmania, Australia.
  
  
  METHODS
  A direct comparison between HbA1c levels and the OGTT results in pregnant women, tested concurrently at the 24-28 gestational week, was undertaken. A full profile of 480 pregnant women during the period from September 2012 to July 2014 was completed. Median and mean age of participants was 29 years (range 18-47 years).
  
  
  METHODS
  A simultaneous prospective assessment of HbA1c versus standard OGTT in a cohort of consecutive pregnant women presenting to our institute was performed.
  
  
  RESULTS
  The number of women who had GDM according to OGTT criteria was 57, representing 11.9% of the evaluated 480 pregnant women. Using a cut-off value for HbA1c at 5.1% (32 mmol/mol) for detecting GDM showed sensitivity of 61% and specificity of 68% with negative predictive value (NPV) of 93%, versus sensitivity of 27% and specificity of 95% with NPV of 91% when using HbA1c cut-off value of 5.4% (36 mmol/mol).
  
  
  CONCLUSIONS
  Our results suggest that pregnant women with an HbA1c of≥5.4% (36 mmol/mol) should proceed with an OGTT. This may result in a significant reduction in the burden of testing on both patients and testing facility staff and resources. Further investigations are required to integrate and optimise the HbA1c as a single, non-fasting, screening tool for GDM.
  
  
  BACKGROUND
  ACTRN12611000739910.
authors.affiliation: Department of Medicine, Launceston General Hospital, Launceston, Tasmania, Australia School of Health Sciences, University of Tasmania, Launceston, Tasmania, Australia Menzies Institute for Medical Research, University of Tasmania, Launceston, Tasmania, Australia.
authors.forename: Alhossain
authors.identifier: http://orcid.org/0000-0002-2399-3311
authors.initials: A
authors.lastname: Khalafallah
authors.affiliation: Department of Obstetrics and Gynaecology, Launceston General Hospital and Royal Hobart Hospital, Launceston, Tasmania, Australia.
authors.forename: Eileen
authors.initials: E
authors.lastname: Phuah
authors.affiliation: School of Health Sciences, University of Tasmania, Launceston, Tasmania, Australia.
authors.forename: Abdul Majeed
authors.initials: AM
authors.lastname: Al-Barazan
authors.affiliation: Department of Obstetrics and Gynaecology, Launceston General Hospital and Royal Hobart Hospital, Launceston, Tasmania, Australia.
authors.forename: Irena
authors.initials: I
authors.lastname: Nikakis
authors.affiliation: Pathology Department, Launceston General Hospital, Launceston, Tasmania, Australia.
authors.forename: Andrea
authors.initials: A
authors.lastname: Radford
authors.affiliation: Pathology Department, Launceston General Hospital, Launceston, Tasmania, Australia.
authors.forename: Wade
authors.initials: W
authors.lastname: Clarkson
authors.affiliation: Pathology Department, Launceston General Hospital, Launceston, Tasmania, Australia.
authors.forename: Clinton
authors.initials: C
authors.lastname: Trevett
authors.affiliation: Pathology Department, Launceston General Hospital, Launceston, Tasmania, Australia.
authors.forename: Terry
authors.initials: T
authors.lastname: Brain
authors.affiliation: Australian National Health and Medical Research Council Clinical Trials Centre, Sydney, New South Wales, Australia.
authors.forename: Val
authors.initials: V
authors.lastname: Gebski
authors.affiliation: Department of Medicine, Launceston General Hospital, Launceston, Tasmania, Australia School of Health Sciences, University of Tasmania, Launceston, Tasmania, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Corbould
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D016640:Diabetes, Gestational / Q000097:blood / Q000175:diagnosis*; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008403:Mass Screening; D008875:Middle Aged; D011247:Pregnancy; D011320:Primary Health Care; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: HbA1c; gestational diabetes; glucose tolerance test; pregnancy; screening