Fasting Blood Glucose Test (FBG)

Fasting blood sugar is a blood test that measures the blood glucose level on an empty stomach to screen for diabetes, prediabetes, or gestational diabetes (during pregnancy). Ideally, you need 10 to 12 hours of fasting before the test.

When does a person need to have their blood glucose measured with this test?

Prediabetes, Type 2 diabetes, and gestational diabetes often have no symptoms at first. A person can have the condition and not know it. Healthcare providers usually order a fasting blood sugar test:

• Pregnant women should make sure that pregnancy hormones are not causing diabetes.
• If a person has diabetes symptoms.
• When someone has ever had higher than normal blood glucose levels.
• If a person has a family history of diabetes or risk factors for diabetes (for example obesity).

What happens during a Fasting Blood Glucose Test?

During a Fasting Blood Glucose Test, a lab technician will collect blood from a vein, typically from the inside of your elbow or from the back of your hand. The test will take only a few minutes. The technician:

• Cleans your skin with an antiseptic wipe
• Places an elastic band, or tourniquet, around your upper arm to help the vein swell with blood
• Inserts a needle in your vein and collect a blood sample in one or more vials
• Removes the elastic band
• Covers the area with a bandage to stop any bleeding
• Place a barcode on your blood sample vial and send them to a lab for analysis

A blood test can be slightly uncomfortable. When the needle punctures your skin, you might feel a prick or pinching sensation. Some people also feel faint or light-headed when they see blood. Afterward, you may have minor bruising, but it will clear up within a few days.

---

---

---