Glucose -Blood- Fasting
Blood glucose after an overnight fast. The simplest screen for diabetes and the number most people know
Also known as FBS, Fasting glucose, Fasting sugar, Sugar fasting, Fasting Blood Sugar (FBS), Fasting Blood Sugar
₹69/-Free collection on orders above ₹500/-
- Reports within
- 8 hours
- Parameter included
- 01see list
- Sample
- Blood
- Fasting
- 10 hours
- Measures
- Level of glucose in the blood after a 10-hour fast
- Identifies
- Prediabetes, diabetes, and low blood sugar
Collected at home
A trained phlebotomist visits at a time you pick, from the next hour
Sealed single-use kit
Opened in front of you, and carried to the lab under controlled conditions
Report within 8 hours
On WhatsApp and email, with any value outside the normal range highlighted
What is the FBS test?
Fasting blood sugar measures the glucose in your blood after you have gone without food overnight, in milligrams per decilitre. Without a recent meal to push it up, the number shows the baseline level your body settles at, which depends on how well insulin is working.
It is the simplest screen for prediabetes and diabetes and the number most people in India already know. A result of 100 to 125 mg/dL is prediabetes, and 126 mg/dL or above on two separate occasions is diabetes. Below 70 mg/dL is low, and matters most for people on diabetes tablets or insulin. Doctors often pair it with a post-meal sugar or HbA1c, because the fasting value can look normal while the after-meal value has already gone up.
You must fast for 10 hours, so the usual plan is an early morning collection at home before breakfast. Water is allowed. The report arrives on WhatsApp and email in 8 hours, so you have the number the same day.
FBS parameters1 measured
Fasting blood glucose
70–100 mg/dL
Blood sugar measured after an overnight fast, the first screen for diabetes, rising when the body makes too little insulin or stops responding to it
Reference ranges are the lab's defaults for adults and are printed on the report beside every value
How to prepare
- Fast for 10 hours before the sample. Nothing to eat or drink except plain water; no tea, coffee, juice or chewing gum.
- Finish dinner by 9 pm and book an early morning slot, before breakfast.
- Take your regular medicines as usual, but ask your doctor whether to delay a morning diabetes tablet or insulin until after the sample.
- Avoid alcohol the evening before and skip heavy exercise on the morning of the test.
Who should take it
Every adult over 30 at least once, and yearly from 40. Anyone with thirst, frequent urination, tiredness, blurred vision, slow-healing wounds or repeated infections. People who are overweight, have high blood pressure, high cholesterol or PCOS, or have a parent or sibling with diabetes. Women planning pregnancy or with past gestational diabetes. Everyone already diagnosed with diabetes, as often as their doctor advises. Anyone with a borderline result last time, who should repeat within three to six months.
Before the visit
Tell your doctor about steroids, water tablets, some blood pressure and psychiatric medicines and oral contraceptives, which can raise sugar, and about any diabetes medicine that could lower it. Acute illness, fever or a poor night's sleep can push the value up on the day.
Why take the FBS test?
- First sugar check: the quickest way to find out whether your sugar is normal, borderline or high.
- Symptoms of diabetes: excessive thirst, frequent urination, unexplained weight loss, tiredness or blurred vision need a sugar test now.
- Family history or weight: a parent or sibling with diabetes, excess weight around the waist, high blood pressure or PCOS all raise the risk.
- Monitoring treatment: for people on diabetes tablets or insulin, the fasting value shows whether the morning dose and evening routine are right.
- Low sugar episodes: shakiness, sweating or confusion before breakfast, especially on diabetes medicine, need a fasting reading to confirm.
Questions about the FBS test
What is the fasting blood sugar test used for?
It is the simplest screen for prediabetes and diabetes, and the routine check for anyone already on diabetes treatment. It also picks up low sugar in people whose tablets or insulin dose may be too high.
How many hours should I fast for a fasting sugar test?
Fast for 10 hours. Nothing to eat or drink except plain water; no tea, coffee, juice, sweets or chewing gum. Finish dinner by 9 pm and book an early morning collection before breakfast.
What sample is taken and how does home collection work?
A small blood sample from the arm. A trained phlebotomist comes to your home early in the morning with a sealed single-use kit, so you can have breakfast as soon as the sample is taken.
What is the normal fasting blood sugar range?
The reference range on the report is 70 to 100 mg/dL. Between 100 and 125 mg/dL is prediabetes. A value of 126 mg/dL or above on two separate days is used to diagnose diabetes.
What does a high or low fasting sugar mean?
High means the body is not handling glucose well overnight, usually because insulin is not working properly; your doctor will confirm with a repeat test or HbA1c. Below 70 mg/dL is low and matters most if you take diabetes medicine, since it may mean the dose is too high.
Who should get a fasting sugar test and how often?
Every adult over 30 at least once and yearly from 40; sooner with excess weight, high blood pressure, PCOS or a family history. Anyone with thirst, frequent urination or unexplained weight loss. People with diabetes test as often as their doctor advises, and borderline results are repeated in three to six months.
How long does the fasting sugar report take?
The report reaches your WhatsApp and email in 8 hours from collection, so you will have the number the same day.
Can I drink water or tea before a fasting sugar test?
Plain water is fine and helps the blood draw. Tea, coffee, milk, juice and anything with sugar or milk will raise the reading, so avoid them until after the sample. Also skip a morning walk or workout beforehand, as exercise can shift the value.
Should I take my diabetes tablet before the fasting sugar test?
Take your other regular medicines as usual, but ask your doctor about the morning diabetes tablet or insulin. Most doctors want the sample taken before the dose, then the dose taken with breakfast straight after. Never skip a dose without checking.
Commonly tested together
Often on the same prescription
What happens after you book
- A phlebotomist is assigned and reaches you in your chosen slot, as soon as the next hour
- The sample is collected with a sealed single-use kit and moved on a cold chain
- The report lands on WhatsApp and email within 8 hours