Finding the right tests…
Emergency services available 24 x 7
Emergency services available 24 x 7
Finding the right tests…
Glucose
BLOOD SUGAR 1HOUR is the glucose reading taken exactly sixty minutes after a glucose drink — a timepoint that shows up in three different glucose protocols, so what it means depends on which one your doctor has ordered. In the 50-gram screening test for gestational diabetes, it's the only post-load number taken. In the 75-gram one-step and 100-gram two-step gestational diabetes protocols, it's one of several timed samples, catching the earliest and usually highest point of your glucose curve, before levels start to fall back down.
This is a single plasma glucose reading, in mg/dL, taken sixty minutes after you finish a glucose drink. In most protocols it captures your blood sugar at or near its peak, since glucose absorbed from the drink typically raises blood levels fastest within the first hour before insulin brings them back down. Depending on which protocol ordered it, this reading may stand alone as a screening result or be one of several values collected during the same visit.
This exact timepoint appears in more glucose-testing protocols than any other single hour mark. In the 50-gram, one-hour gestational diabetes screen, it is the entire test — a reading of 140 mg/dL or below is generally read as normal. In the 75-gram one-step protocol used to diagnose gestational diabetes, and in the 100-gram two-step confirmatory test, the one-hour draw is one of several samples, with an abnormal cutoff of 180 mg/dL in both.
Glucose usually peaks within the first hour after a sugary drink, before insulin has had much time to bring it back down, which is why an abnormal one-hour value often signals a stronger insulin response is needed than your body is providing. A single high one-hour reading inside a multi-point test isn't diagnostic by itself in the two-step protocol — at least two of the four values need to be abnormal — but in the one-step 75-gram protocol, this one value alone is enough to confirm gestational diabetes if it crosses 180 mg/dL.
It usually captures your blood sugar close to its peak after a glucose drink. Glucose absorption is fastest in the first hour, before insulin has had much time to bring levels back down.
That cutoff applies specifically to the 50-gram, one-hour gestational diabetes screening test. In the 75-gram or 100-gram protocols, the one-hour cutoff is different, at 180 mg/dL, so the same number can mean something different depending on the protocol.
It depends on the protocol. The 50-gram, one-hour screening test doesn't require fasting, but the 75-gram and 100-gram protocols that also check a one-hour value do require a fasting sample first.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
In the one-step 75-gram protocol, yes — a one-hour value of 180 mg/dL or higher alone confirms the diagnosis. In the two-step 100-gram protocol, at least two of the four checked values need to be abnormal.
Checking one hour in addition to two hours gives a fuller picture of your glucose curve. It shows both how high your sugar rises early on and how well your body brings it back down by two hours.
That depends on the protocol. In the 50-gram screen, this is usually the only sample. In the 75-gram or 100-gram protocols, further samples follow at two hours, and sometimes three hours.