Blood Sugar Level Tests & Testing

Blood sugar tests measure your body's ability to process sugar. The results may indicate whether you have an underlying disease or condition such as prediabetes or diabetes.

Fasting Blood Sugar Test

A fasting blood sugar test measures the amount of sugar (glucose) in your blood after eight hours without food or drink (other than water).

Normal Fasting Blood Sugar

Normal fasting blood sugar levels fall between 70 milligrams per deciliter (mg/dL), or 3.88 millimoles per liter (mmol/L), and 100 mg/dL or 5.55 mmol/L.

Prediabetes Levels

Fasting blood sugar levels from 100 mg/dL (5.55 mmol/L) to 125 mg/dL (6.94 mmol/L) may be an indicator of prediabetes.

Type 1 or 2 Diabetes Levels

Fasting blood sugar levels on their own do not help distinguish between type 1 and type 2 diabetes, but fasting blood glucose levels above 126 mg/dL (7.00 mmol/L), are consistent with either type 1 or type 2 diabetes when accompanied by classic diabetes symptoms such as increased thirst or hunger, weight loss, frequent urination or blurred vision. Your doctor may repeat this and other tests at different times in order to confirm the diagnosis.

Two-Hour Glucose Tolerance Test

A glucose tolerance test measures how your body reacts to sugar. Your doctor will ask you to drink a liquid containing sugar and then draw blood from your arm two hours later.

Normal Two-Hour Test Blood Sugar Levels

Normal blood glucose tolerance for a two-hour test is under 140 mg/dL (7.77 mmol/L).

Prediabetes Levels

Two-hour glucose levels between 140 mg/dL (7.77 mmol/L) and 199 mg/dL (11.05 mmol/L) may be an indicator of prediabetes.

Type 1 or 2 Diabetes levels

Blood sugar of 200 mg/dL (11.11 mmol/L) or higher two hours after drinking the sugar solution may indicate type 1 or 2 diabetes. Your doctor may repeat this and other tests to confirm a diagnosis.

Glycated Hemoglobin Test

Glycated hemoglobin tests (also called glycosylated hemoglobin tests or hemoglobin A1C tests), reflect average blood sugar levels over the two to three months prior to testing. This test is not used in the diagnosis of prediabetes or diabetes, but rather to gauge how well a diabetic patient is managing their blood sugar.

What is Normal

This will vary from lab to lab as normal standards have not been established for this test.

Blood Sugar Self-Testing

If you have diabetes or prediabetes, your doctor may order self-testing of your blood sugar levels and prescribe glucose self-testing supplies. These generally include a glucose meter (glucometer), test strips, lancets, lancing device and control solution. If you have a valid prescription for diabetes self-testing supplies, Diabetes Supply Co may be able to ship your supplies direct, and you may qualify for a free meter. For more details, click here.