Labcorp Glucose Tolerance Test: What to Expect

The test is used to look for gestational diabetes or another problem with glucose handling. You may first have a blood sample, drink a glucose solution, then have further samples taken at scheduled times. The clinic or laboratory will tell you whether fasting is required, how long to allow and what you may drink. A result outside the expected range does not by itself explain how you feel; your maternity team interprets it alongside your history and other results. See the [Glucose Tolerance Test](/treatments/pregnancy-and-birth-care/glucose-tolerance-test/) page for more detail.

Follow the laboratory's instructions about fasting, medicines and arrival time. Bring water if permitted, wear clothing that allows easy access to your arm and plan to remain at the site during the timed collection. Tell staff if you vomit, feel faint or cannot complete the drink. Do not change your diet or diabetes medicines unless the clinician who prescribed them tells you to. Keep your [Antenatal Care Package](/treatments/pregnancy-and-birth-care/antenatal-care-package/) appointments so results can be reviewed in context.

Contact the laboratory or maternity team if you are unsure whether to fast, miss a timed sample or cannot attend. During or after the test, ask for help promptly if you become very dizzy, faint, confused, unusually weak or repeatedly vomit. Afterward, follow up when the result is available; a diagnosis may lead to advice about food, monitoring or treatment, while an unclear result may need a repeat or alternative assessment.

Ask why the test is recommended, whether you need to fast, which medicines to take, how long the visit may take, and when and how your result will be explained. Ask what happens if you cannot tolerate the drink or if the result is outside the expected range.