Fasting plasma glucose test (FPG)
The FPG blood test measures your blood glucose level at a single point in time. To get the most reliable results, it is best to get this test in the morning, after fasting for at least 8 hours. Fasting means having nothing to eat or drink, except sips of water.
Oral glucose tolerance test (OGTT)
The OGTT is a more expensive test and is not so easy to perform.
Hemoglobin A1c test
A simple blood test, A1c ("glycosylated hemoglobin") is performed on a sample of blood taken from a finger or a small vial of the arm. It should not be confused with daily monitoring at home that allows some people with diabetes
to measure your blood sugar levels at the time,
The A1c test paints a picture of your average blood sugar level for the past 3 months.
Video credits to LiJe’s A to Z YouTube channel