Finding the right tests…
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Finding the right tests…
Glucose
PGBS-50 gms measures your blood sugar exactly one hour after drinking a 50-gram glucose solution, with no fasting beforehand. It is the initial screening step doctors use to check for gestational diabetes, usually between the 24th and 28th week of pregnancy. Because there's only one blood draw and no fasting requirement, it's simpler to schedule than a full glucose tolerance test, but a result above the cutoff does not confirm diabetes by itself — it means your doctor will likely order the longer 100-gram, three-hour test to confirm or rule it out.
This test reports the glucose concentration in your blood plasma, in mg/dL, exactly 60 minutes after you finish drinking the 50-gram glucose solution. A single blood sample taken from a vein is enough — there is no fasting sample and no later draw with this test alone. The result is compared against a screening threshold rather than a full diagnostic range, and it stands on its own without needing a same-day fasting value for context.
This is a screening test, not a diagnostic one. Doctors use it as the first step in the widely used two-step approach to gestational diabetes screening: everyone gets the 50-gram, one-hour challenge, and only those with a raised result move on to the longer confirmatory test.
A one-hour reading of 140 mg/dL or lower is generally read as a normal screen. A result above that means your doctor will usually schedule the longer 100-gram, three-hour glucose tolerance test to confirm or rule out gestational diabetes.
Because this test measures your response to a glucose load rather than a fasting baseline, you don't need to prepare by fasting beforehand — you can eat normally and take the test at any point in your prenatal visit schedule, which is part of why it's used as a first-pass screen for every pregnant woman rather than only those with risk factors.
No. This test is designed to be taken without fasting, at any time of day, regardless of when you last ate.
It means the screen is positive, not that you have gestational diabetes. Your doctor will usually order the longer 100-gram, three-hour glucose tolerance test to confirm or rule out the diagnosis.
A one-hour reading of 140 mg/dL or below is generally read as a normal screen, per MedlinePlus guidance on pregnancy glucose screening. Ranges can vary slightly by lab, so check the figure printed on your own report.
Possibly, if your risk factors change or your doctor wants to recheck later in pregnancy. This depends on your individual history and is a decision for your obstetrician.
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.
This test uses a smaller, 50-gram glucose load and is only a screening step, always followed up if positive. The 75-gram test uses a larger load and can be diagnostic on its own, depending on the protocol your doctor follows.
Yes. Since no fasting is required, you can eat and drink as usual before coming in for this test.
No. This is a screening test only. A raised result identifies who needs further, more detailed testing, not a final diagnosis.