You passed your glucose test if your blood sugar came back below 140 mg/dL on the one-hour screening. That’s the standard cutoff most providers use, though some clinics set the bar lower at 130 mg/dL. If your result falls below your provider’s threshold, no further testing is needed. If it’s at or above that number, it doesn’t automatically mean you have gestational diabetes, but you will need a longer follow-up test to find out.
What a Passing Result Looks Like
The one-hour glucose challenge test (sometimes called the “glucola test”) is a screening, not a diagnosis. You drink a sugary solution containing 50 grams of glucose, and your blood is drawn one hour later. A result below 140 mg/dL is considered normal by most labs and providers.
When you check your results in a patient portal, you’ll typically see your blood sugar number alongside a reference range. If your value falls within or below that range, the result is usually flagged as “normal.” If it’s above the range, the lab may label it “abnormal” or “high,” sometimes marked with an “H” or highlighted in a different color. These labels can feel alarming, but an abnormal screening result simply means more testing is warranted. Results generally come back within a few business days, though turnaround times vary by lab.
What Happens If Your Number Is High
A result between 140 and 189 mg/dL means your provider will schedule a three-hour glucose tolerance test. This is the diagnostic test that actually confirms or rules out gestational diabetes. A result of 190 mg/dL or higher on the initial screening is high enough that many providers will diagnose gestational diabetes without requiring the longer test.
For the three-hour test, you fast for eight hours beforehand. A fasting blood sample is drawn first, then you drink a stronger glucose solution containing 100 grams of sugar. Your blood is drawn again at one hour, two hours, and three hours after you finish the drink. That means four total blood draws over the course of the morning.
Three-Hour Test Passing Numbers
To be diagnosed with gestational diabetes on the three-hour test, at least two of your four blood draws need to meet or exceed specific thresholds:
- 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 only one value is elevated, you typically pass. If two or more are above their cutoffs, you’ll receive a gestational diabetes diagnosis. So it’s possible to have one high reading on the three-hour test and still not have gestational diabetes.
Why Some Clinics Use Different Cutoffs
You may notice your provider uses 130 mg/dL as the passing threshold for the one-hour screening instead of 140. Both are considered acceptable. A lower cutoff catches more cases of gestational diabetes but also sends more people to the three-hour test who will ultimately pass it. Your provider chooses the threshold based on their practice guidelines and your individual risk factors.
There’s also a completely different testing approach used by some providers, called the one-step method. Instead of the 50-gram screening followed by a 100-gram diagnostic test, the one-step method skips straight to a two-hour test using 75 grams of glucose. The passing thresholds for this version are different: fasting below 92 mg/dL, one-hour below 180 mg/dL, and two-hour below 153 mg/dL. Unlike the three-hour test where two values must be elevated, a single high value on the one-step test is enough for a diagnosis. If you’re unsure which version you took, your provider’s office can clarify.
Why a High Screening Doesn’t Mean You Failed
The one-hour glucose challenge is designed to cast a wide net. It intentionally flags more people than will ultimately be diagnosed with gestational diabetes. Many women with results in the 140 to 189 range go on to pass the three-hour test without any issues. The screening is meant to identify who needs closer evaluation, not to deliver a final answer.
Several everyday factors can nudge your blood sugar higher on test day. What you ate in the hours before the test, how much physical activity you had recently, stress levels, and even recent illness can all influence the result. This is one reason the follow-up test requires fasting and multiple blood draws: it gives a much more accurate picture of how your body actually handles sugar over time.
Reading Your Results in a Patient Portal
If you’re staring at your results online and trying to figure out what they mean, here’s what to look for. Find the number next to “glucose” or “blood glucose” and compare it to the reference range listed on the same line. For the one-hour screening, a number under 140 (or under 130 if your clinic uses the stricter cutoff) means you passed. If you took the three-hour test, you’ll see multiple glucose values listed at different time points. Compare each one to the thresholds above and count how many are elevated.
Keep in mind that labs sometimes report results in different units. In the U.S., blood sugar is almost always reported in mg/dL. If you see results in mmol/L, the one-hour screening cutoff of 140 mg/dL is equivalent to 7.8 mmol/L. Your portal should display the appropriate reference range for whichever unit is used.