Oral glucose tolerance test in diabetes, the old method revisited

Table 1 Differences in the oral glucose tolerance test used in clinics and in basic research

Subjects	Clinical Practice	Basic Research
Main aims	Diagnosis	Assay of responses
Applications	75 g for 2hPG	2 g for 2hPG
New method	75 g for 30 min or1hPG	Unknown
Identification	Shape of curve	Calculated AUC
Fasting PG	Important	Included
Plasma insulin	Reference	Important
Conscious	Clear	Anesthesia
Cost-effective	No	Yes
Interpretation	Diet and exercise	Pain sensation
Circadian factor	Yes	Can be regulated
Bias	Allergy to glucose	Artificial errors
Fasting concerns	Yes	No
Reproducibility	Not so good	Reliable
Drug interaction	Yes	No
Indications	Anemia or borderline PG	Less
Others	Age or renal glycosuria	Genetics

1hPG: 1-h post-glucose load glycemia; 2hPG: 2-h post-glucose load glycemia; AUC: Area under the curve; PG: Post-glucose load glycemia.