Fasting Blood Glucose
Also known as: FBG, Fasting Blood Sugar
Blood glucose measured after at least 8 hours of fasting — a standard diagnostic test for diabetes.
Fasting blood glucose is measured after no caloric intake for at least 8 hours. It is the most commonly used test to screen for and diagnose diabetes, alongside A1C and the oral glucose tolerance test (OGTT).
Diagnostic thresholds: under 100 mg/dL is normal; 100–125 mg/dL is prediabetes (impaired fasting glucose); 126 mg/dL or above on two separate occasions is diagnostic for diabetes.
For ongoing management, fasting glucose — typically measured upon waking before breakfast — provides a baseline that reflects overnight glucose production and the effect of any basal insulin dose. CGM systems display fasting glucose automatically each morning as part of the continuous reading stream.
High fasting glucose despite good daytime control may indicate the dawn phenomenon (early-morning cortisol causing glucose rise), Somogyi effect (rebound hyperglycemia after nocturnal hypoglycemia), or insufficient basal insulin.
Frequently asked
What is Fasting Blood Glucose?
Blood glucose measured after at least 8 hours of fasting — a standard diagnostic test for diabetes. Fasting blood glucose is measured after no caloric intake for at least 8 hours. It is the most commonly used test to screen for and diagnose diabetes, alongside A1C and the oral glucose tolerance test (OGTT).
How does Fasting Blood Glucose relate to Medicare coverage?
Medicare Part B covers most durable medical equipment related to Fasting Blood Glucose. Contact us to verify your specific coverage for related diabetic supplies.
Where can I get diabetic supplies related to Fasting Blood Glucose in Phoenix?
We deliver Medicare-covered diabetic supplies throughout the Phoenix metro area. Call us or complete the form above to verify your coverage.