Quick answer
The Oral Glucose Tolerance Test (OGTT / GTT) costs ₹500 at Live Line Health Care. Measures your blood sugar before and after a standard glucose drink over 2 hours at a centre. 8–12 hours overnight fast. Done at a Live Line centre, where you stay about 2 hours for timed samples after a glucose drink.
Also known as: OGTT, GTT, Glucose Tolerance Test, Oral Glucose Tolerance Test, 75g OGTT, 75 g Glucose Test, Sugar Load Test, GTT in Pregnancy
What is the Glucose Tolerance (OGTT) Test?
The Oral Glucose Tolerance Test (OGTT, also called GTT) shows how your body handles a fixed amount of sugar. After an overnight fast, a blood sample is taken. You then drink a solution containing 75 g of glucose within 5 minutes, and further samples are taken at set times, usually at 2 hours and sometimes at 1 hour as well. Because everyone gets the same glucose dose, the results can be compared with standard cut-offs, which a normal meal cannot provide.
This test is done only at a Live Line centre, not with home collection. The samples must be drawn at exact times, and you need to stay seated and resting for about 2 hours, without eating, walking about or smoking, so the reading is not disturbed. The OGTT is more sensitive than fasting sugar or HbA1c, and it can pick up impaired glucose tolerance that other tests miss. It is the main test for diagnosing diabetes in pregnancy, usually between 24 and 28 weeks. The glucose challenge test is a shorter, non-fasting screen in pregnancy, while the OGTT is the full diagnostic test.
What it measures: Plasma glucose after an overnight fast and at set times, usually 2 hours, after drinking 75 g of glucose.
Parameters included (3)
- Fasting Plasma Glucose (mg/dL)
- 1 Hour Plasma Glucose, if requested (mg/dL)
- 2 Hour Plasma Glucose (mg/dL)
Why is this test done?
- Diagnosing diabetes in pregnancy (gestational diabetes)
- Confirming diabetes or prediabetes when fasting sugar or HbA1c is borderline
- Finding impaired glucose tolerance in people at high risk
- Checking women with PCOS or a past history of gestational diabetes
- Rechecking sugar tolerance after delivery in women who had gestational diabetes
When should you get tested?
- Pregnancy, especially between 24 and 28 weeks, when your doctor asks for it
- A fasting sugar of 100 to 125 mg/dL or HbA1c of 5.7% to 6.4%
- A raised glucose challenge test result in pregnancy
- Obesity, PCOS or a strong family history of diabetes
- A previous baby weighing more than 4 kg at birth
How to prepare for the Glucose Tolerance (OGTT) Test
- 1Eat your normal diet, including your usual rice, roti or other carbohydrates, for 3 days before the test. Do not cut down on food beforehand.
- 2Fast for 8 to 12 hours overnight, with plain water only.
- 3Come to a Live Line centre in the morning and plan to stay about 2 to 2.5 hours. Bring water, something to read and a light snack for after the last sample.
- 4Do not eat, smoke or walk around between samples. Tell staff if you vomit after the drink, as the test may need to be done on another day.
- 5Tell staff about any medicines such as steroids, and follow your doctor's advice about diabetes medicines on the test day.
Glucose Tolerance (OGTT) Test normal range
| Parameter | Typical reference range |
|---|---|
| Non-pregnant adults, fasting | Normal below 100 mg/dL · Diabetes 126 mg/dL or higher |
| Non-pregnant adults, 2 hours | Normal below 140 mg/dL · Impaired 140–199 mg/dL · Diabetes 200 mg/dL or higher |
| Pregnancy (75 g), fasting | Gestational diabetes if 92 mg/dL or higher |
| Pregnancy (75 g), 1 hour | Gestational diabetes if 180 mg/dL or higher |
| Pregnancy (75 g), 2 hours | Gestational diabetes if 153 mg/dL or higherone value at or above any limit is enough |
Some doctors in India use a single non-fasting 75 g test in pregnancy, with gestational diabetes diagnosed at a 2 hour value of 140 mg/dL or more. Your doctor will tell you which method applies. Ranges are typical adult values and vary between labs, age and sex. Always use the range printed on your report and discuss results with your doctor.
Understanding your results
- A normal fasting value with a 2 hour value of 140 to 199 mg/dL is called impaired glucose tolerance, a form of prediabetes that often improves with diet, exercise and weight loss.
- A 2 hour value of 200 mg/dL or higher in a non-pregnant adult meets the cut-off for diabetes. Your doctor will usually confirm this before starting treatment.
- In pregnancy, even one value at or above the limit means gestational diabetes. Your doctor will plan diet changes, sugar checks and sometimes medicines to protect you and your baby.
- Women who had gestational diabetes are usually advised to repeat the glucose test some weeks after delivery and then at regular intervals, because their future risk of diabetes is higher.
Glucose Tolerance (OGTT) Test – FAQs
What is the price of the Glucose Tolerance (OGTT) Test?
The Oral Glucose Tolerance Test (OGTT / GTT) costs ₹500 at Live Line Health Care, at all 45 centres.
Why must the OGTT be done at a centre?
Samples must be taken at exact times after the glucose drink, and you need to stay seated, resting and without food for about 2 hours. Moving around or eating changes the result. Doing it at a Live Line centre keeps the timing and conditions right, so the test is not offered with home collection.
What is the difference between GCT and OGTT?
The GCT is a shorter screening test in pregnancy, with a 50 g glucose drink, no fasting and one sample at 1 hour. The OGTT uses 75 g of glucose after a fast and is the test used to make a diagnosis. A raised GCT is usually followed by an OGTT.
Can I drink water during the glucose tolerance test?
Small sips of plain water are usually fine, but avoid anything else, including tea, coffee, juice and chewing gum. Food, smoking and exercise can all change the readings. Ask the staff at the centre if you are unsure about anything during the test.
What if I vomit after the glucose drink?
Tell the staff straight away. If you vomit soon after the drink, your body has not received the full glucose dose, and the result would not be valid. The test is usually rescheduled for another day. Some people find it easier to sip the drink steadily over the 5 minutes.
Is the OGTT safe in pregnancy?
Yes. It is the standard test for gestational diabetes and the glucose drink is safe for you and your baby. Some women feel mild nausea or light-headedness, so resting during the test helps. Your obstetrician will decide the best week for it, commonly between 24 and 28 weeks.
How is OGTT different from fasting sugar and HbA1c?
Fasting sugar shows a single overnight reading, and HbA1c shows your 3 month average. The OGTT tests how your body copes with a sugar load, so it can find problems the other two miss. It takes longer, which is why doctors use it when other results are borderline or in pregnancy.
Where can I get the Glucose Tolerance (OGTT) Test done?
At any of our 45 Live Line Health Care centres in 40 cities across Andhra Pradesh and Telangana, including Hyderabad, Visakhapatnam, Warangal, Kakinada and Nellore. This test is done at a centre, not at home.
Medical disclaimer: This information is for general awareness only and is not a substitute for professional medical advice. Please consult a qualified doctor to interpret your results and before starting or changing any treatment.