You passed your glucose test if your blood sugar came back below the cutoff your provider uses, which is typically 140 mg/dL for the one-hour screening most pregnant women take. Some clinics set that bar lower at 130 or 135 mg/dL, so the number you need to beat depends on your specific provider’s threshold. If you’re waiting on results or trying to interpret a number you saw in your patient portal, here’s how to make sense of it.
One-Hour Screening Test Results
The one-hour glucose challenge test is the standard screening done between weeks 24 and 28 of pregnancy. You drink a sugary solution, wait an hour, and get your blood drawn. No fasting is required beforehand. A blood sugar level below 140 mg/dL (7.8 mmol/L) is considered normal at most practices, and that means you passed.
If your result falls between 140 and 189 mg/dL, you didn’t necessarily “fail” in the sense that you have gestational diabetes. It means your result was above the screening cutoff and you’ll need the longer, more definitive three-hour glucose tolerance test. Think of the one-hour test as a filter: it catches everyone who might have an issue so the diagnostic test can sort out who actually does.
A result of 190 mg/dL or higher on the one-hour test is high enough that many providers will diagnose gestational diabetes without requiring the three-hour follow-up.
One important detail: some clinics use a lower cutoff of 130 mg/dL instead of 140. If your result is, say, 136 mg/dL, you might pass at one practice but get sent for further testing at another. This is why checking your specific provider’s threshold matters more than Googling a single number.
Three-Hour Diagnostic Test Results
If you were sent for the three-hour test, this one requires overnight fasting (typically 8 to 12 hours). Your blood is drawn four times: once fasting, then at one, two, and three hours after drinking a higher-concentration glucose solution. Each draw has its own cutoff value, and you need to exceed the threshold on two or more of the four draws to receive a gestational diabetes diagnosis.
The specific cutoff numbers vary slightly depending on which set of criteria your provider follows. Your results sheet or patient portal will typically show your value next to a reference range for each time point. If all four of your values fall within the normal range, you passed. If only one value is elevated, most providers still consider that a pass, though they may recommend dietary monitoring or a retest later in pregnancy.
Non-Pregnancy Glucose Tests
If you’re not pregnant and had a fasting blood glucose test or an A1C test as part of routine bloodwork, the thresholds are different. For A1C, which measures your average blood sugar over roughly three months, the ranges break down clearly: below 5.7% is normal, 5.7% to 6.4% falls into the prediabetes range, and 6.5% or above indicates diabetes. An A1C of 6% corresponds to an average blood sugar of about 126 mg/dL, while 7% corresponds to roughly 154 mg/dL.
For a fasting plasma glucose test, normal is generally below 100 mg/dL. Results between 100 and 125 mg/dL suggest prediabetes, and 126 mg/dL or higher on two separate tests points to diabetes. If your number is in the prediabetes range, that’s not a diagnosis of diabetes, but it is a signal that your body is starting to have trouble managing blood sugar.
When Results Take Longer Than Expected
Most glucose test results come back within a few business days, though the exact turnaround varies by lab. If you took the one-hour screening at your OB’s office, some practices run the test in-house and can tell you the same day. Others send samples to an outside lab, which adds a day or two. The three-hour test almost always goes to a lab and takes a bit longer to process since there are multiple blood draws to analyze.
If your provider’s office hasn’t called, that’s often (but not always) a good sign. Many practices operate on a “no news is good news” policy for normal results and only call when something needs follow-up. Still, check your patient portal if you have one. Lab results frequently post there before anyone calls.
Factors That Can Skew Your Results
Illness, physical activity levels, and certain medications can all affect glucose test accuracy. If you were fighting a cold or infection when you took the test, your blood sugar may have read higher than your true baseline. Likewise, unusually intense exercise right before the test or skipping the fasting requirement for a test that required it could throw off numbers in either direction.
If you think something may have affected your result, let your provider know. A single borderline number taken during a stomach bug isn’t the same as a truly elevated result, and your provider can decide whether a retest makes sense. This is especially relevant if you barely crossed the cutoff on the one-hour screening and are anxious about the three-hour test ahead.
What Happens If You Didn’t Pass
If your one-hour screening came back above the cutoff, the next step is the three-hour glucose tolerance test, usually scheduled within a week or two. Many women who “fail” the one-hour screening go on to pass the three-hour test with no issues. The screening is deliberately sensitive, designed to cast a wide net.
If you’re ultimately diagnosed with gestational diabetes, the initial management is usually dietary changes and blood sugar monitoring at home. Most women with gestational diabetes have healthy pregnancies and deliveries. The diagnosis means closer monitoring, not an emergency, and your care team will walk you through what changes to expect for the rest of your pregnancy.