Insulin (75 gm Glucose Test)

A 75 gm glucose test is an oral glucose tolerance test used to assess how the body handles sugar. After an overnight fast a baseline blood sample is taken, the patient drinks a 75‑gram glucose solution, and blood is measured at set intervals (commonly 1 and 2 hours). Results help diagnose impaired glucose tolerance, diabetes, and gestational diabetes.

There's no single universally accepted insulin cut‑off after a 75 g oral glucose load. Typical fasting insulin is about 2–20 μU/mL (12–120 pmol/L). Two‑hour post‑OGTT insulin is often considered normal if under ~60 μU/mL (≈360 pmol/L); higher values suggest hyperinsulinemia/insulin resistance. Laboratories use different assays and units, so interpret results with clinical context.

Use a digital kitchen scale to weigh 75 g of glucose powder exactly. If you have a pre-measured OGTT sachet, dissolve it in about 250–300 mL (one glass) of room-temperature water and drink promptly (within 5 minutes). Do not substitute table sugar (sucrose); if using dextrose tablets, add up the grams on the label to reach 75 g.

If you mean a blood glucose level of 75 mg/dL, that falls within the normal fasting range (about 70–99 mg/dL) and is not high. If you mean 75 mg (milligrams) of glucose taken orally, that is very small—far less than the 75 g (grams) used in an oral glucose tolerance test. Clarify the units and consult a clinician if symptomatic.

To increase the chance of a reliable 75 g oral glucose tolerance test result, follow the lab’s instructions: eat your normal meals for several days before (don’t deliberately cut carbs), fast 8–14 hours before the test, drink only water, avoid alcohol and heavy exercise the day before, keep calm and seated during the test, and take prescribed medications unless told otherwise. Tell staff about illnesses or medications.

The insulin tolerance test (ITT) is a supervised diagnostic test that gives IV insulin to produce controlled hypoglycaemia to assess pituitary‑adrenal (ACTH–cortisol) and growth hormone reserve and to evaluate insulin sensitivity. Glucose and hormone levels are sampled at intervals while staff monitor for hypoglycaemia. It’s contraindicated in seizure disorders, coronary artery disease, or in patients unable to tolerate low blood glucose; emergency glucose must be available.