Glucose tolerance tests are used to help diagnose diabetes mellitus or gestational diabetes, which occurs during pregnancy. The procedure basically consists of these steps:
- Confirm that the patient has been fasting.
- Collect a fasting blood glucose specimen.
- Have the patient drink the dose of glucose solution required by the procedure.
- Collect blood at standard timed intervals.
Blood, or blood and urine specimens, are then checked for glucose levels. The patient should be instructed to remain in the facility and remain seated between blood collections. The phlebotomist should check on the patient periodically between blood collections, especially during the first hour. For some patients, the glucose solution may cause nausea and vomiting and the test may need to be terminated.