Fasting blood sugar test is done to measure the glucose level in your blood, after a certain time of fasting. In healthy people insulin hormone reduces the blood sugar level after fasting. Insulin hormone does not function properly in diabetics so glucose level is found more than expected in fasting blood sugar test.
Fasting blood sugar test can be used in diagnosis of diabetes and also to check the treatment. Best time for fasting blood sugar test is morning. At least 8 hours of fasting is needed but 10-12 hours of fasting is preferred.
Purpose; why the fasting blood sugar test is performed?
Your doctor may request the fasting blood sugar test if you have the common symptoms of diabetes like;
- Frequent urination
- Feeling very thirsty and hungry
- Weight loss
- Blurred vision
- Numbness or pain in hands and feet
- Slow healing sores, bruises, cuts
- Dry mouth
Preparation for fasting blood sugar test
Fasting blood sugar test is done after at least 8 hours of fasting so you should not eat anything for at least 8-10 hours
Also don’t drink anything except water that may affect the fasting blood sugar test result like soda, milk, alcohol etc
If you have diabetes please ask your doctor about about diabetes medicine usage before fasting blood sugar test
How the fasting blood sugar test is performed?
A tube of blood is needed for fasting blood sugar test ; your health professional; ( doctor,nurse,technician) will
- Wrap an elastic band around your upper arm
- Clean the skin inside of your elbow or on the back of your hand with an antiseptic
- Insert a needle in a suitable vein (you may feel a little a pain for a few seconds)
- Place the tube and collect blood
- Remove the needle and elastic band
- Put a piece of cotton or bandage over the site
- Normal: 70-100 mg/dL
- Prediabetes: 100-126 mg/dL
- Diabetes: Higher than 126 mg/dL
All blood collection process takes 1-2 minutes at most
Fasting blood sugar test normal values
Your doctor may request additional tests like OGTT ( oral glucose tolerance test) if your fasting blood sugar test result is higher than normal.