Quick Facts
- Sample: Blood
- Fasting: Fasting for 8–12 hours is required; check with your physician before stopping medications. Four blood draws are taken over 3 hours after drinking a glucose solution, and you must remain at the lab until testing is complete.
- Turnaround: 1–2 business days. May take longer based on weather, holiday, or lab delays.
What This Test Measures
This test measures your blood glucose level at four separate points to help diagnose gestational diabetes. The process begins with a fasting glucose measurement, followed by a glucose solution you drink, then three additional glucose measurements taken at one hour intervals over the next three hours (glucose at 1 hour, 2 hours, and 3 hours).
Because this test involves four timed blood draws collected over several hours, it is a multi specimen diagnostic protocol, not a single blood draw. It reflects how your body processes glucose over time after a glucose challenge, which is different from a single random or fasting glucose check.
Benefits
- Provides four timed glucose measurements across a 3-hour period
- Supports diagnosis of gestational diabetes using an ACOG-based protocol
- Captures how glucose changes after a glucose challenge
- Includes a fasting glucose result as a baseline reference
- Offers a structured, multi-draw approach to glucose evaluation
Who Is This Test For?
- Pregnant women following up on an abnormal glucose screening result
- Pregnant women with risk factors for gestational diabetes, such as obesity or PCOS
- Women with a family history of diabetes seeking further glucose evaluation
- Pregnant women who previously delivered a baby weighing 9 pounds or more
- Women whose healthcare provider has recommended diagnostic glucose testing
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. Do I need to fast or prepare for this test?
Fasting for 8-12 hours is required before this test. Three days before testing, you should discontinue all nonessential medication affecting glucose metabolism, and you should check with your physician before stopping any medications. Do not stop prescribed medication unless instructed by your healthcare provider.
2. How quickly will I get results?
Results are typically available in 1-2 business days, though this may take longer based on weather, holidays, or lab delays.
3. What can my results tell me?
Each of the four glucose measurements collected during this test contributes to a picture of how your body processes glucose after a glucose challenge. A healthcare provider uses the full set of fasting, 1 hour, 2 hour, and 3 hour glucose values together, rather than any single reading, to evaluate glucose tolerance during pregnancy.
4. What factors can affect my results?
Not completing the required fasting period, eating or drinking anything other than water before the test, or leaving the lab before all four collections are finished can affect the accuracy of your results. Discontinuing or continuing medications that affect glucose metabolism without your physician's guidance may also influence your measurements.
5. How do I interpret the results?
Interpreting results from this multi-draw glucose tolerance protocol depends on how your fasting, 1-hour, 2-hour, and 3-hour glucose values compare together, along with your pregnancy history, risk factors, and any related lab findings. This test does not provide a standalone interpretation, and a single elevated or normal value does not by itself confirm or exclude gestational diabetes.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
6. What should I do if my results are abnormal?
Bringing your results to a qualified healthcare provider is the appropriate next step if any of your glucose values fall outside the expected range. Your provider can review your full set of results in the context of your pregnancy and determine whether additional evaluation is appropriate. This test does not diagnose gestational diabetes on its own, and no treatment decisions should be made from the results alone.
Pre-test preparation
Fasting for 8-12 hours is required. Three days before testing, discontinue all nonessential medication affecting glucose metabolism. Check with your physician before stopping any medications. Do not stop prescribed medication unless instructed by your healthcare provider. This test requires four blood draws. The first will be taken when you arrive at the lab. You will then be given a glucose solution to drink. Three subsequent collections will be taken at 1-hour intervals. You must remain at the lab until the final collection is taken.
