Ajax Harwood Clinic
75 g oral glucose tolerance test (OGTT)
This test is useful only in specific situations — it's not right for everyone who asks about it.
What this test is
The 75 gram oral glucose tolerance test, or OGTT, checks how your body handles sugar over time. You drink a sweet liquid. Then your blood is drawn a few times over about 2 hours. It is the best way to check blood sugar if you are being diagnosed with PCOS. It catches problems that one blood draw can miss. It is also used to check for diabetes in pregnancy. It is used for some people at higher risk of type 2 diabetes. If none of these apply to you, a simpler blood test is usually enough. The full 2-hour test is not needed in that case.
Want to see the full clinical reasoning? The reference we use for this test is open to anyone — it is detailed and written for clinicians, and you are welcome to read it.
Open the clinician reference →Looking for other tests, or more on a condition an ND raised? Explore ask.ajaxharwoodclinic.com →
General health information for Ajax Harwood Clinic patients and the public — not medical advice, and not a substitute for seeing your own doctor. Last reviewed 2026-09-23.