Fasting blood sugar (FBS) is a type of blood glucose test that measures the amount of glucose in your blood after you have not eaten for at least 8 hours. It is often the first test done to check for prediabetes and diabetes. During the test, a healthcare professional will tie a band around your upper arm to help the veins in your arm fill with blood. Then, they will insert a clean needle into a vein in your arm and draw blood into a vial that’s attached to the needle and labeled with your personal information. After the test, the healthcare provider will send the blood sample to a lab for testing.

The FBS test is not only used to screen for diabetes and prediabetes, but it also evaluates how well diabetes patients’ medications or dietary modifications work. The FBS test normal range is 70 to 100 mg/dl, and the normal fasting sugar level is less than 100 mg/dl. If the test results show a level of 100 to 125 mg/dL (5.6 to 6.9 mmol/L), it means you have impaired fasting glucose, a type of prediabetes. This increases your risk of developing type 2 diabetes, and you should consult with your healthcare provider. A level of 126 mg/dL (7 mmol/L) or higher usually means you have diabetes.