What is this test?
Fasting blood glucose measures the level of glucose in the blood after at least 8 hours of fasting. It is the most basic test for screening for diabetes and prediabetes; observing the fasting period is important for an accurate result.
When is it requested?
Diabetes mellitus screening and monitoring of response to treatment
What does a high fasting blood glucose result mean?
A high fasting glucose may suggest prediabetes or diabetes; however, not fasting long enough, stress or illness can also cause a temporary rise.
- Not fasting properly, a sugary drink or gum in the morning
- Stress, lack of sleep, fever or acute illness
- Certain medicines such as corticosteroids
- Insulin resistance and prediabetes
- Diabetes
- Less commonly, pancreatic or hormonal disorders
What does a low fasting blood glucose result mean?
A low fasting glucose is often due to temporary causes such as prolonged fasting or delayed sample processing; if it recurs with symptoms, it should be investigated.
- Delayed processing of the blood sample (cells in the tube use up glucose)
- Fasting for a very long time
- Intense exercise or alcohol before the test
- Diabetes medicines or insulin
- Severe liver or kidney disease
- Rarely, hormone deficiencies or an insulin-producing tumor
My result is outside the reference range. What should I do?
Fast for 8–12 hours before the test, drinking only water. A single result does not diagnose diabetes; your doctor may repeat the test or order HbA1c or a glucose tolerance test.
Reference ranges depend on the method, age and sex; always use the range printed on your report. This information is for general guidance only; consult your doctor for diagnosis and treatment.
Sample information
- Sample type: Serum
- Tube / container: Yellow-top tube
- Sample volume: 1 mL
Preparation
Fasting sample recommended.
Testing and results
- Method: Enzymatic
- Run schedule: Daily
- Turnaround time: 3 hours
Price and appointment
Add the test to your list to receive a price quote by e-mail, or call +90 850 640 07 30 / message us on WhatsApp (+90 537 301 22 14). You can have the test done at our branches or with our home blood collection service. Results can be viewed online with your Turkish ID number (or passport number for foreign nationals).