Fasting Blood Glucose
Alternate Names : FBS, Fasting Blood Sugar
This test measures the amount of glucose in the blood. It is called
fasting because the level is measured at least 8 hours after a person last ate or
Who is a candidate for the test?
If a doctor suspects a person may have diabetes or pre-diabetes due
to certain symptoms or risk factors, this test may be done.
How is the test performed?
In order to measure the amount of glucose in the blood, a blood
sample is taken from a vein on the forearm or hand. First, the skin over the vein
is cleaned with an antiseptic. Next, a rubber tube called a tourniquet is tied
around the upper arm. This enlarges the veins in the lower arm by restricting
blood flow through them. A fine needle is gently inserted into a vein, and the
tourniquet is removed. Blood flows from the vein through the needle and is
collected in a syringe or vial for testing in the laboratory. After the needle is
withdrawn, the puncture site is covered for a short time to prevent bleeding.