Screening and Diagnosis
Current guidelines differ, but the ADA recommends that all adults be screened for prediabetes and type 2 diabetes starting at age 45. Screening is also recommended for adults under 45 who are overweight and have an additional risk factor, such as high blood pressure or a family history of diabetes.
There are several tests that can be used to check for diabetes. All of them measure your blood sugar level, but under different circumstances. The tables below describe each test and explains what the results mean.
|
Fasting Plasma Glucose (FPG) Test |
|
| 80–99 mg/dL | Normal |
| 100–125 mg/dL | Prediabetes or impaired fasting glucose (IFG) |
| >126 mg/dL | Diabetes |
|
Oral Glucose Tolerance Test (OGTT) |
|
| <140 mg/dL | Normal |
| 141–199 mg/dL | Prediabetes or impaired glucose tolerance (IGT) |
| 200 mg/dL or higher | Diabetes |
|
Hemoglobin A1c (HbA1c) Test |
|
| 3.0%–6.0% | Normal |
| 6.1%–6.4% | High risk (the A1c test is not routinely used to diagnose prediabetes) |
| 6.5%+ | Diabetes |
Note: To confirm a diagnosis of diabetes, a repeat test must be done on a different day. This is not required for a diagnosis of prediabetes unless you are considering treatment with medication, in which case a second test should be done. Medication for prediabetes is not recommended without a confirmed diagnosis of both impaired glucose tolerance (IGT) and impaired fasting glucose (IFG).
A random blood sugar test may be used to diagnose diabetes if there are also distinct symptoms present that strongly suggest diabetes. A random glucose test may be given at any time, whether or not you've recently eaten, and a result of 200 mg/dL or higher indicates diabetes.
