Fasting Blood Sugar (FBS)
A simple morning blood test that measures your baseline glucose — a first-line check for diabetes and pre-diabetes.
The Fasting Blood Sugar test is a first-line check for diabetes and pre-diabetes, measuring your baseline glucose after an overnight fast for a clear, reliable reading.
About the Fasting Blood Sugar (FBS) Test
This test measures the level of glucose in your blood after you have not eaten for at least eight hours. Because food temporarily raises blood sugar, fasting provides a stable baseline that reveals how well your body regulates glucose. Elevated results can indicate pre-diabetes or diabetes long before symptoms such as thirst, fatigue or frequent urination appear, making it an essential part of routine screening for adults in Hat Yai.
Preparation and turnaround
An overnight fast of at least eight hours is required, so a morning appointment is ideal; water is permitted. A quick venous sample is taken and results are usually available within one working day. If your reading is raised, your doctor may recommend an HbA1c or glucose tolerance test to confirm the diagnosis.
Frequently asked questions
How long should I fast?
Fast for at least eight hours before the test. Plain water is allowed, but avoid food, sweetened drinks and coffee during the fasting period.
What is a normal fasting glucose level?
Generally below 5.6 mmol/L is considered normal, 5.6–6.9 mmol/L suggests pre-diabetes, and 7.0 mmol/L or above on repeat testing indicates diabetes. Your report shows the exact range.
Should I take my medication before the test?
Continue essential medication with water unless your doctor advises otherwise, but mention any diabetes medication when you attend.
Some tests require fasting. We'll confirm any preparation (such as fasting for 8–10 hours) when we confirm your appointment. When in doubt, ask us at booking.
Related tests
HbA1c (Diabetes) Test
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Measures the hormone that controls your blood sugar — valuable for investigating insulin resistance, metabolic health and unexplained low sugar.
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A dynamic test that shows how your body handles a glucose load over time — the definitive check for diabetes and gestational diabetes.
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