Blood Sugar Testing Guide: What Numbers Actually Mean and What to Ask Your Doctor
You can't rely on how you feel to catch blood sugar problems early — insulin resistance develops over years while symptoms stay mild. This guide explains the three core tests and introduces a "gray zone" that most doctors don't flag but is the best window for action.
The three tests
- Fasting glucose: Normal <100 mg/dL, Prediabetes 100–125, Diabetes 126+
- Hemoglobin A1C: Normal <5.7%, Prediabetes 5.7–6.4%, Diabetes 6.5%+ (reflects a 3-month average)
- Oral Glucose Tolerance Test (OGTT): 2-hour reading — Normal <140 mg/dL, Prediabetes 140–199, Diabetes 200+
The "gray zone"
Fasting glucose of 90–99 mg/dL or A1C of 5.4–5.6% is technically "normal" but often trending upward — and it's the easiest stage to reverse, since no medication is indicated and full reversal is realistic. The article recommends tracking trends year-over-year (not just single results), retesting every 3–6 months in this range, and specific questions to ask a doctor, such as "What were my numbers 1–2 years ago?" and "At what number would you recommend medication?"
It also compares continuous glucose monitors vs. fingerstick meters for at-home tracking, and reviews research on reversal: 50–70% of people reverse prediabetes with sustained lifestyle changes over 6–12 months.