75-gram, 2-hour Glucose Challenge Test
About 75-gram, 2-hour Glucose Challenge Test
| Field | Value |
|---|---|
| Also Known As | GCT 75 gm test, 75g glucose challenge test, 2-hour glucose challenge test, DIPSI test, oral glucose tolerance test (OGTT) and glucose tolerance test (GTT) |
| Sample Type | Plasma (venous blood) |
| Fasting Required | Varies: the DIPSI method requires no fasting; the standard protocol requires 8 to 10 hours of fasting. Follow your lab's instructions. |
| Report Time | 1 Day |
| Recommended For | All genders and ages; primarily pregnant women at 24 to 28 weeks for gestational diabetes screening; adults with diabetes risk factors |
| Price | Starting at ₹180 |
What Is a 75-gram, 2-hour Glucose Challenge Test?
The GCT 75GM test is a blood sugar test that checks how well your body processes sugar. You drink a 75-gram glucose solution, and a blood sample is collected exactly 2 hours later to measure your plasma glucose level. It is commonly prescribed for pregnant women to screen for gestational diabetes and also for adults suspected of having prediabetes or type 2 diabetes. The test is also called the GCT 75 gm test, DIPSI test, or 2-Hour Glucose Challenge.
What Does the 75-gram, 2-hour Glucose Challenge Test Measure?
This test measures a single value: the level of glucose in your blood plasma two hours after you consume a standard 75-gram glucose drink. The result tells your doctor how efficiently your body is clearing glucose from the bloodstream after a sugar load.
| Parameter | What It Tells Your Doctor |
|---|---|
| 2-hour plasma glucose | Whether your body is processing glucose normally or whether levels remain too high after two hours |
Why is a 75-gram, 2-hour Glucose Challenge Test Done?
A doctor may order this test to screen for glucose-related conditions or to investigate symptoms linked to blood sugar imbalance.
Common Symptoms That May Require This Test
The following symptoms may prompt a doctor to recommend a GCT 75GM test procedure:
- Excessive thirst or dry mouth
- Frequent urination, especially at night
- Unexplained fatigue or low energy
- Blurred vision
- Unexplained weight loss
- Slow-healing cuts or wounds
Conditions This Test Can Help Detect
This test can help identify several conditions related to blood sugar regulation:
- Gestational diabetes (high blood sugar during pregnancy)
- Type 2 diabetes or prediabetes
- Impaired glucose tolerance (blood sugar raised but not yet at diabetic levels)
- Insulin resistance (when the body does not respond properly to insulin)
- Reactive hypoglycaemia (blood sugar dropping too low after eating)
Glucose Challenge Test 75 Gm During Pregnancy
This test is a routine part of antenatal care. Most pregnant women are advised to have a GCT 75 gm screening between 24 and 28 weeks of pregnancy. It may be done earlier if routine urine tests show high glucose or if the mother has risk factors for diabetes. Detecting gestational diabetes early helps reduce the risk of complications such as a high birth-weight baby or preterm delivery.
How to Prepare and What to Expect
Preparation for the GCT 75GM test is straightforward, but following the instructions carefully helps ensure accurate results.
Do You Need to Fast?
Fasting depends on the method your lab uses. Under the DIPSI protocol, the standard approach used for many gestational diabetes screenings, no fasting is required. Under the traditional OGTT protocol, you would need to fast for 8 to 10 hours beforehand. Always confirm with Lupin Diagnostics at the time of online booking for the GCT 75GM test.
Practical Tips Before Your Test
Keep the following points in mind before your appointment:
- Eat normally for at least three days before the test, including at least 150 grams of carbohydrates daily.
- Avoid unusually strenuous exercise in the days leading up to the test.
- Inform your doctor or the collection staff about all medications and supplements you are currently taking, as some can affect your results.
- Wear a loose-fitting top or a top with sleeves that roll up easily to allow easy access to your arm.
- Plan to remain seated and resting for the full 2-hour waiting period at the collection centre.
Step-by-Step Procedure
Here is what to expect on the day of your GCT 75GM test procedure:
- Arrive at the Lupin Diagnostics centre or receive the home collection visit at your scheduled time.
- A trained phlebotomist will collect a small blood sample (approximately 2 ml of plasma) from a vein in your arm if a baseline reading is required.
- You will be given a glucose drink containing 75 grams of glucose dissolved in about 250 to 300 ml of water. Drink it fully within five minutes.
- Wait quietly for two hours. Remain seated; do not eat, drink anything other than small sips of plain water, or move around excessively during this time.
- After exactly two hours, a second blood sample is collected from your vein. This is the key sample tested for plasma glucose.
- The test is now complete. Your sample is stored under refrigeration and dispatched to the NABL-accredited Lupin Diagnostics laboratory for analysis.
Factors That Can Affect Accuracy
The following factors may influence your results:
- Current illness, infection, or recent traumatic injury
- Medications such as corticosteroids (steroids), diuretics (water pills), anticonvulsants, aspirin-type drugs, or oral contraceptives
- Prolonged bed rest or physical inactivity in the days before the test
- A diet very low in carbohydrates in the days leading up to the test
- Hormonal conditions such as polycystic ovary syndrome (PCOS) or Cushing's syndrome
Understanding Your GCT 75GM Results
Your result is a single plasma glucose reading taken two hours after the glucose drink. The table below shows how results are generally interpreted.
| Category | 2-Hour Plasma Glucose |
|---|---|
| Normal (for adults) | Less than 140 mg/dL (7.8 mmol/L) |
| Impaired glucose tolerance (prediabetes) | 140 to 199 mg/dL (7.8 to 11.0 mmol/L) |
| Diabetes (diagnostic threshold) | 200 mg/dL (11.1 mmol/L) or above |
| Gestational diabetes (DIPSI criteria) | 140 mg/dL (7.8 mmol/L) or above |
Disclaimer: These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Certain situations can affect how your glucose tolerance test (GTT) results should be read. If you are unwell, have a recent infection, or are recovering from an injury, the test may not reflect your true glucose tolerance, and your doctor may ask you to repeat it once you have recovered. Several medications, including steroids, diuretics, and some blood pressure drugs, can push glucose levels higher than normal. Let your doctor know about any such factors before your results are interpreted.
How to Maintain Healthy Levels
The following general wellness habits support healthy blood sugar levels:
- Eat a balanced diet with plenty of fibre, vegetables, and whole grains, while limiting refined sugars and processed foods.
- Aim for at least 150 minutes of moderate physical activity each week, such as brisk walking.
- Maintain a healthy body weight, as even modest weight reduction can meaningfully improve the body's ability to manage glucose.
Lupin Diagnostics 75-gram, 2-hour Glucose Challenge Test Price and Home Collection
The GCT 75GM test cost at Lupin Diagnostics starts at ₹180, and home collection is available across cities. The table below shows approximate prices across major Indian cities.
| City | Approximate Price ( ₹) |
|---|---|
| BHOPAL | 90 |
| CHENNAI | 120 |
| HYDERABAD | 120 |
| KOLKATA | 120 |
| NAVI MUMBAI | 180 |
| PUNE | 150 |
Disclaimer: Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
GCT 75GM test online booking is quick and straightforward.
- Select the Glucose Challenge Test 75 Gm After 2 Hours on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within 1 day.
Home Collection
Lupin Diagnostics offers a GCT 75GM test home collection facility across multiple cities in India. All samples are processed in NABL-accredited laboratories. Your digital report is delivered directly to you, making the process convenient without compromising on quality.
Frequently Asked Questions
The GCT 75GM test and the oral glucose tolerance test (OGTT) both use a 75-gram glucose drink and measure blood sugar after two hours. The key difference is that the GCT under the DIPSI method does not require fasting, while the full OGTT typically requires 8 to 10 hours of fasting and may involve multiple blood samples. Your doctor will specify which protocol your test follows.
Under the DIPSI method, which is widely used for gestational diabetes screening in India, no fasting is required before the 75-gm GCT. However, some laboratories use a standard fasting protocol. Always confirm fasting requirements with Lupin Diagnostics when you complete your GCT 75GM test online booking.
A result at or above 140 mg/dL (using DIPSI criteria) may indicate gestational diabetes. For non-pregnant individuals, a result of 200 mg/dL or above may indicate diabetes. Your doctor will review your result alongside your symptoms and health history and may recommend further tests before making any diagnosis.
Yes. While the test is most commonly associated with pregnancy screening, it is also used to assess glucose tolerance in non-pregnant adults of any gender. It can help detect prediabetes, type 2 diabetes, insulin resistance, and impaired glucose tolerance.
Some people feel mildly nauseated, dizzy, or sweaty after drinking the glucose solution. If you experience severe symptoms or vomit after drinking the glucose, inform the healthcare staff immediately. Vomiting can invalidate the test, and it may need to be rescheduled.
The test takes approximately 2.5 to 3 hours from start to finish. You need to stay at the collection centre or remain available at home (if opting for home collection) during the two-hour waiting period between drinking the glucose solution and the final blood draw.
75-gram, 2-hour Glucose Challenge Test
