ABSTRACT
We aimed to determine a threshold value that perfectly demarcates women at high risk
for gestational diabetes mellitus (GDM) in the Turkish population. One thousand gravid
women of 24 to 32 weeks of gestation were given 50 g, 1-hour glucose screening tests.
A 100 g, 3-hour glucose tolerance test (GTT) was performed on all patients whose screening
test plasma glucose value was 130 mg/dL or greater. The sensitivity and specificity
of each screening test value was found, and the GDM rate of each value was calculated.
Three-hundred-and-five patients were identified for GTT and 66 were shown to have
GDM with two or more abnormal values in GTT. The incidence of GDM was found to be
6.6%. The maximum specificity and sensitivity were met at 140 mg/dL. However, this
value underestimated 12% of patients with GDM, and the lowest value for a positive
GTT appeared to be 134 mg/dL. We recommend a 135 mg/dL threshold for GTT since this
threshold accurately diagnoses almost all women with GDM while eliminating unnecessary
GTT.
Keywords
Gestational diabetes - glucose screening - carbohydrate intolerance
