A1c (Hemoglobin A1c):
-Reflects your average blood glucose levels over the past 2–3 months.
-Measures glucose attached to hemoglobin in red blood cells (which live ~120 days).
-Used to diagnose and monitor diabetes:
Normal: <5.7%
Prediabetes: 5.7–6.4%
Diabetes: ≥6.5%
Limitation: Doesn’t capture blood sugar spikes or insulin function—only the end result (glucose exposure).
Fasting Insulin:
Measures insulin concentration in your blood after an 8–12 hour fast.
Reveals how hard your pancreas is working right now to manage blood sugar.
High levels (>10–25 μIU/mL, depending on lab) signal insulin resistance—your cells aren’t responding to insulin, so your pancreas pumps out more to compensate.
-Can detect metabolic dysfunction years before A1c rises. Many with "normal" A1c have high fasting insulin, meaning they’re already on the path to diabetes.
