title: Diagnostic ability of elevated 1-h glucose challenge test.
abstract: To determine whether a threshold of a 1-h glucose challenge test (GCT) eliminates the need for a 3-h glucose tolerance test (GTT).
  
  
  
  A retrospective cohort of patients undergoing GTT after GCT was ⩾140 mg dl(-1). Gestational diabetes mellitus (GDM) was diagnosed using National Diabetes Data Group (NDDG) and Carpenter-Coustan (CC) criteria. Sensitivity, specificity and predictive values were calculated for 1-h GCT values of 160 to 220 mg dl(-1).
  
  
  
  Of 6218 patients, 988 (15.9%) had an elevated GCT and 753 (12.1%) underwent a GTT. In all, 165 (2.7%) were diagnosed with GDM using NDDG criteria, and 250 (4.0%) by CC criteria. The positive predictive value of a 1-h of GCT ⩾200 mg dl(-1) for GDM was 68.6% by NDDG and 80.0% for GDM by CC criteria.
  
  
  
  Although the predictive value of an elevated 1-h ⩽200 mg dl(-1) for GDM was high, 1 in 3 to 1 in 5 women would be overdiagnosed with GDM if the 3-h GTT was omitted.
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St Louis, St Louis, MO, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Temming
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St Louis, St Louis, MO, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Tuuli
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St Louis, St Louis, MO, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Stout
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St Louis, St Louis, MO, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Macones
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St Louis, St Louis, MO, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Cahill
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000175:diagnosis*; D005260:Female; D005951:Glucose Tolerance Test / Q000379:methods*; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014481:United States
chemical_list: D001786:Blood Glucose