Fasting insulin and HOMA-IR: the metabolic signal that precedes A1c by years

By the time HbA1c crosses 5.7% and your PCP calls you "pre-diabetic," your fasting insulin has likely been elevated for 5-10 years. A normal HbA1c is the last metric to change; fasting insulin is one of the first. If you've been told "your blood sugar is fine," run this number before celebrating.