Gestational diabetes
Screening

Condition
2-hour glucose
Fasting glucose
HbA1c
HbA1c
Unit
mmol/l(mg/dl)
mmol/l(mg/dl)
mmol/mol
DCCT %
Normal
<7.8 (<140)
<6.1 (<110)
<42
<6.0
Impaired fasting glycaemia
<7.8 (<140)
≥6.1(≥110) & <7.0(<126)
42-46
6.0–6.4
Impaired glucose tolerance
≥7.8 (≥140)
<7.0 (<126)
42-46
6.0–6.4
Diabetes mellitus
≥11.1 (≥200)
≥7.0 (≥126)
≥48
≥6.5

Question: How is the diagnosis of GDM determined? 
Answer: When the plasma glucose level is found to be higher than 126 mg/dl (7.0 mmol/l) after fasting, or over 200 mg/dl (11.1 mmol/l) on any occasion and if this is confirmed on a subsequent day, the diagnosis of GDM is made and no further testing is required.