most primary care physicians measure your A1c to screen for progression to diabetes but it is an inferior measurement to capture early metabolic dysfunction.
They should be measuring fasting insulin levels. Here's why:
Discussion
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.