A normal fasting blood glucose level is lower than 95 mg/dL (5.3 mmol/L). One hour after drinking the glucose solution, a normal blood glucose level is lower than 180 mg/dL (10 mmol/L). Two hours after drinking the glucose solution, a normal blood glucose level is lower than 155 mg/dL (8.6 mmol/L).
3-Hour Glucose Tolerance Test
- You should eat your normal diet prior to the day of testing.
- Do not eat, drink, smoke, or exercise for at least 8-12 hours before your first blood sample is taken.
- This test may take up to four hours to complete.
- Consider bringing something to read or a project to work on while waiting.
You will be asked to drink a liquid that contains glucose. Your blood will be drawn 1 hour after you drink the glucose solution to check your blood glucose level.
For example, glucose testing may be done as part of routine screening during a general health exam. For people with diabetes, glucose levels are often checked both while fasting and after meals to provide the best control of diabetes.
How long does it take to get results?
- complete blood count (CBC): 24 hours.
- basic metabolic panel: 24 hours.
- complete metabolic panel: 24–72 hours.
- lipid panel: 24 hours.
Results of urine and blood tests can take about seven working days to come back from the laboratory. The person ordering the test should tell you whether you need to make an appointment to come back, or whether you should phone for your results.
If a patient has two or more abnormal values during the three-hour test, then the test overall is considered abnormal. Your doctor will likely diagnose you with gestational diabetes if you fail the three-hour test.
Odds of passingThe truth about this test is that the one-hour test is pretty easy to “fail,” and many people do! They make the threshold low enough so that they catch anyone who could be having an issue, just in case. The levels on the three-hour test are much more reasonable and easier to meet.
Avoid breads, cereals and fruit juices. Example of foods for lunch would be lettuce/salad with any kind of meat. Green beans, broccoli and any leafy vegetable. Avoid fried foods, no bread, soft drinks with sugar or sweet tea.
3-Hour Glucose Test
| Interval | Abnormal reading |
|---|
| Fasting | 95 mg/dl or higher |
| One hour | 180 mg/dl or higher |
| Two hours | 155 mg/dl or higher |
| Three hours | 140 mg/dl or higher |
If untreated, gestational diabetes can cause problems for your baby, like premature birth and stillbirth. Gestational diabetes usually goes away after you have your baby; but if you have it, you're more likely to develop diabetes later in life.
2-Hour Oral Glucose Tolerance Test (OGTT)—non pregnancy
| Glucose Level | Interpretation |
|---|
| Less than 100 mg/dL (5.5 mmol/L) | Normal glucose tolerance |
| 100 to 125 mg/dL (5.6 to 6.9 mmol/L) | Impaired fasting glucose (prediabetes) |
| 126 mg/dL (7.0 mmol/L) and above | Elevated (hyperglycemia is present) |
Unlike other types of diabetes, gestational diabetes usually goes away on its own and soon after delivery blood sugar levels return to normal, says Dr. Tania Esakoff, clinical director of the Prenatal Diagnosis Center. "There is no need for gestational diabetes to take away from the joys of pregnancy."
Gestational diabetes raises your risk of high blood pressure, as well as preeclampsia — a serious complication of pregnancy that causes high blood pressure and other symptoms that can threaten the lives of both mother and baby.
Yes, you can walk around during the glucose test. A normal amount of walking shouldn't impact the test results.
Even if you drink it black, coffee can interfere with blood test results. That's because it contains caffeine and soluble plant matter, which might skew your test results.
Warning Signs of Gestational Diabetes
- Sugar in the urine.
- Unusual thirst.
- Frequent urination.
- Fatigue.
- Nausea.
- Blurred vision.
- Vaginal, bladder and skin infections.
YOU MUST BE FASTING for this test. DO NOT eat or drink anything except WATER for at least 8 hours before the test. You may drink plain water ONLY. Do NOT drink coffee, tea, soda (regular or diet) or any other beverages.
How the Test will Feel. Most women do not have side effects from the glucose tolerance test. Drinking the glucose solution is similar to drinking a very sweet soda. Some women may feel nauseated, sweaty, or lightheaded after they drink the glucose solution.
It sometimes helps to have eaten something a few hours before the screening test. If you vomit soon after you've gotten the drink down, you'll have to come back another day and repeat the test. But most women get through it just fine.
Drinking water before a fasting blood sugar test can actually decrease blood sugar levels, or at least prevent levels from getting too high. Water allows more glucose to be flushed out of the blood.
To increase how fast your insulin works and prevent false positive results (in other words, to maximize your chance of passing the three-hour GTT), you will need to prepare by including at least 120g of carbohydrates in your diet per day for three days prior to your test (see table of foods containing carbohydrates).
Walk-ins are also welcome.Please note that not all lab locations offer all services. When visiting a lab, you should bring the Labcorp test request form from a health care professional requesting the laboratory testing.
Overview. The glucose challenge test measures your body's response to sugar (glucose). The glucose challenge test is done during pregnancy to screen for gestational diabetes — diabetes that develops during pregnancy.
Walgreens pharmacists conduct blood glucose tests with a quick fingerstick. Tests are available to people 18 and older at select stores during pharmacy hours daily with no appointment necessary. All customers getting a blood glucose test will receive a pharmacist consultation to help better understand results.
Oral Glucose Tolerance Test (OGTT)You will need your blood drawn every hour for 2 to 3 hours for a doctor to diagnose gestational diabetes. High blood glucose levels at any two or more blood test times—fasting, 1 hour, 2 hours, or 3 hours—mean you have gestational diabetes.
gtt normal valueThe OGTT normal range for fasting results is between 100 – 125 mg/dL for prediabetes, 126 mg/dL or greater for diabetes and greater than 92 mg/dL for gestational diabetes.
