tests used for diagnosis:
1) fasting plasma glucose test (FPG)
o measures your blood glucose after you have gone at least 8 hours without eating.
o used to detect diabetes or pre-diabetes.
o the preferred test for diagnosing diabetes due to convenience
o most reliable when done in the morning
| Plasma Glucose Result (mg/dL) | Diagnosis |
| 110 and below | Normal |
| 110 to 125 | Pre-diabetes
(impaired fasting glucose) -more likely to develop type 2 diabetes) |
| 126 and above | Diabetes* |
Table 1. Fasting Plasma Glucose Test
*Confirmed by repeating the test on a different day.
2) oral glucose tolerance test (OGTT)
o measures your blood glucose after you have gone at least 8 hours without eating and after you drink a glucose-containing beverage. (75 grams of glucose dissolved in water; 100 grams for pregnant wome)
o blood will be taken before drinking glucose-containing solution, and again every 30 to 60 minutes after drinking the solution. The test takes up to 3 hours.
o can be used to diagnose diabetes or pre-diabetes, gestational diabetes.
| 2-Hour Plasma Glucose Result (mg/dL) | Diagnosis |
| 139 and below | Normal |
| 140 to 199 | Pre-diabetes
(impaired glucose tolerance) |
| 200 and above | Diabetes* |
Table 2. Oral Glucose Tolerance Test
o For diagnosis of gestational diabetes, blood glucose levels are checked 4x during the test. o If blood glucose levels are above normal at least twice during the test, you have gestational diabetes.
| When | Plasma Glucose Result (mg/dL) |
| Fasting | 105 or higher |
| At 1 hour | 190 or higher |
| At 2 hours | 165 or higher |
| At 3 hours | 145 or higher |
Table 3. Gestational Diabetes: Above-Normal
Results for the Oral Glucose Tolerance Test
3) random plasma glucose test (RPG) o doctor checks your blood glucose without regard to when you ate your last meal.
o random blood glucose level of 200 mg/dL or more + presence of the following symptoms, can mean that you have diabetes:
· increased urination
· increased thirst
· unexplained weight loss
· Other symptoms include fatigue, blurred vision, increased hunger, and sores that do not heal
o This test, along with an assessment of symptoms, is used to diagnose diabetes but not pre-diabetes.
o Positive test results should be confirmed by repeating the fasting plasma glucose test or the oral glucose tolerance test on a different day.