Oral glucose tolerance test (OGTT)
A timed test that tracks glucose, and ideally insulin, after a standard glucose drink. The most detailed common test for insulin resistance.
An oral glucose tolerance test measures how the body handles a standard dose of glucose over time. After a fasting blood draw, you drink a measured glucose solution, and blood is taken again at intervals, usually at two hours.
A basic OGTT tracks glucose only. The more informative version for PMOS also measures insulin at each point. That insulin-paired version can reveal the early, compensated stage of insulin resistance, where the body keeps glucose normal by releasing extra insulin, which a glucose-only test cannot see.
Of the common options (fasting glucose, fasting insulin, HOMA-IR, OGTT), the OGTT with insulin is the most detailed and the most likely to surface insulin resistance that simpler tests miss. It takes longer and is not always ordered by default, so it can be worth asking about specifically.