Glucose Tolerance Test in Chennai
Asked to do a sugar test that takes two hours, or booked in for gestational diabetes screening? A glucose tolerance test in Chennai measures how your body handles a measured glucose drink over time, which catches problems a single fasting sugar can miss. It needs fasting and a stay of about two hours, so our team schedules you early and keeps the timings exact, because on this test timing is the result.
Glucose Tolerance Test, booked in 30 seconds
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What is a Glucose Tolerance Test?
The Glucose Tolerance Test in Chennai checks how well your body handles sugar. Many people take this test to find out if they have diabetes, prediabetes, or gestational diabetes during pregnancy. The Glucose Tolerance Test (also called OGTT or GTT) shows how your blood sugar rises and falls after you drink a sweet liquid.
The glucose tolerance test measures how quickly your body clears sugar from the blood. After an overnight fast, you drink a measured amount of sugar solution. Blood samples are taken before and after the drink to see how your body responds. It is different from a simple fasting blood sugar test or HbA1c test. This test looks at your body’s reaction over a few hours.
Why Might You Need a Glucose Tolerance Test?
Doctors may suggest a GTT if:
- Your fasting blood sugar or other results are borderline
- You have risk factors for diabetes such as family history, excess weight, or high blood pressure
- You are pregnant and need screening for gestational diabetes
- You have symptoms like increased thirst, frequent urination, tiredness, or blurred vision
- Your doctor wants to check for impaired glucose tolerance (prediabetes)
How is the GTT Test Done?
The most common version is the two-hour oral glucose tolerance test:
- You arrive in the morning after fasting (nothing to eat or drink except water for at least 8 hours).
- A blood sample is taken to measure your fasting blood sugar.
- You drink a sweet liquid containing 75 grams of glucose. You must finish it within five minutes.
- You stay at the hospital and rest. You cannot eat, smoke, or do heavy activity during the test.
- Another blood sample is taken two hours after the drink. Sometimes a sample is also taken at one hour.
The whole process usually takes about two to three hours. Bring something to read or pass the time.
Preparation for the Test
- Eat your normal meals for at least three days before the test (include enough carbohydrates).
- Fast for 8 to 12 hours overnight. Water is allowed.
- Avoid smoking, caffeine, and vigorous exercise on the morning of the test.
- Tell your doctor about any medicines you take, as some can affect results.
- Wear comfortable clothes with sleeves that can be rolled up easily.
Understanding Your Results
Results are based mainly on the blood sugar level two hours after the glucose drink, measured in mg/dL. The OGTT normal range is below 140 mg/dL.
Your doctor will also look at the fasting result and your full health picture. A diagnosis of diabetes is usually confirmed with a second test on another day.
| 2-Hour Blood Sugar Level (non-pregnant adults) | What It Means |
|---|---|
| Below 140 mg/dL | Normal |
| 140 to 199 mg/dL | Prediabetes (impaired glucose tolerance) |
| 200 mg/dL or higher | Diabetes |
Reference ranges vary between laboratories. Always read your report against the range printed on it, and with your doctor.
These figures are for non-pregnant adults. Cut-offs used in pregnancy are different and lower, and a value that reads as borderline here may be diagnosed as gestational diabetes. Your obstetric team will interpret a pregnancy result using the protocol your doctor follows.
Why Choose Unittas Hospital for GTT Test?
At Unittas Hospital, our team supports you through every stage of the test, including the glucose tolerance test in pregnancy. From clear preparation guidance to careful sample collection and easy-to-understand result discussions, we make the process simple and comfortable. With convenient locations in Tambaram and OMR Kelambakkam, flexible appointment times, and access to experienced doctors when needed, you receive attentive, patient-focused care in a calm setting.
If you need a reliable OGTT test in Chennai or want clear guidance on your results, the team at Unittas Hospital is ready to help. Take control of your blood sugar health. Book your appointment with us today.
Further reading: types of high-risk pregnancies and how they are managed.
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Glucose tolerance test questions
You should not eat or drink anything except water for at least 8 hours (usually overnight). The test is best done in the morning.
Yes. Plain water is allowed. Avoid tea, coffee, juice, or any drink with calories.
It is very sweet, similar to a sugary soft drink or flat soda. Some people find it unpleasant, but most manage to finish it.
No. You need to stay and rest quietly so the results are accurate. Walking around or eating will affect the test.
It is mainly used for diabetes and prediabetes. It is also the standard test for gestational diabetes in pregnancy and is sometimes used for other rare conditions.
Some people feel nauseous or bloated. Tell the staff straight away. In rare cases the test may need to be stopped and repeated another day.
Results are usually ready within a few hours to one working day. Your doctor will discuss them with you.
Yes. The amount of sugar in the drink is adjusted according to the child’s weight (up to a maximum of 75 grams).
Usually two blood samples are taken (fasting and two-hour). Sometimes a one-hour sample is also collected. Each sample is a standard blood draw from the arm.
An impaired result found early can often be improved with weight, diet and activity changes. Your doctor will set a review date to check whether it is moving in the right direction.
Yes. Some medicines, including steroids and certain blood pressure drugs, can change results. Always inform your doctor about everything you are taking.
They measure different things. HbA1c shows average blood sugar over two to three months. The glucose tolerance test shows how your body handles a sugar load in real time. Doctors choose the right test for your situation.
It is better to wait until you feel well. Illness can temporarily raise blood sugar and affect accuracy.
For gestational diabetes, the amount of sugar, the timing of blood samples, and the cut-off values may differ. Your obstetric team will give you exact instructions.
Your doctor will confirm the pattern, start dietary and lifestyle measures, and in pregnancy arrange closer monitoring of both you and the baby. Medication is added only if those measures are not enough.
All diagnostic tests at Unittas
Visit our Chennai labs
Both branches run the same NABH grade lab. Walk in during clinic hours, or call us to book your visit.
Tambaram
7, Duraiswamy Reddy Street, West Tambaram, Chennai 600045
Mon to Sat, 8 am to 8 pm. Sun, 9 am to 1 pm.
OMR Kelambakkam
141/1, Kazhipattur Village, OMR Main Rd, Kelambakkam 603103
Mon to Sat, 8 am to 8 pm. Sun, 9 am to 1 pm.
A two hour test that a single sugar reading can miss.
Book an OGTT at Unittas, come fasting, and our team keeps every draw on schedule so the result is reliable.
Book: Glucose Tolerance Test
Fasting test with a two-hour stay at the hospital. Report the same day. Our care team calls you back shortly.
Thank you. Our care team will call you back shortly to confirm your glucose tolerance test slot.