Medical Information Only
This site provides general health information for educational purposes only — not a substitute for professional medical advice. Always consult your doctor about your results.
Your doctor ordered an HbA1c. The number came back. Now you're lost in search results full of clinical language. We explain it in plain English — with an interactive range tool.
Internal Medicine, Metabolic Disease ·
The essentials — before you read the full guide below.
A 3-month average of your blood sugar. Unlike daily glucose, it can't be gamed by eating well the day before.
Below 5.7% is normal. 5.7–6.4% is prediabetes. 6.5% or above meets the diabetes diagnostic threshold.
Unlike fasting glucose, HbA1c can be drawn any time of day — no preparation required.
A result of 5.7–6.4% is a warning, not a verdict. Diet and exercise can bring it back to normal.
Reference Ranges
Use the interactive slider below, or read the range cards for a full clinical breakdown.
Drag to see what your HbA1c (Glycated Haemoglobin) means
The Science
HbA1c measures how much glucose has bonded to haemoglobin in your red blood cells. Since red blood cells live ~3 months, this bond accumulates over that entire period — creating an honest long-term average you can't cheat with a good meal the night before.
Your RBCs circulate for 90–120 days. Sugar bonds throughout — creating a rolling 3-month average.
In a healthy person, about 4–6% of haemoglobin molecules have glucose attached at any given time.
A meal before your blood draw doesn't affect the result. Draw any time, any day.
When to Test
These are the most common reasons a HbA1c (Glycated Haemoglobin) test is requested — from symptoms to routine screening.
Classic early warning signs. Kidneys working overtime filtering glucose leads to dehydration and frequent urination.
High-priorityWhen cells can't access glucose efficiently, exhaustion persists even after a full night's sleep.
High-priorityHigh glucose changes the shape of the eye's lens — an under-recognised diabetes warning sign.
High-priorityFirst-degree relatives with type 2 diabetes significantly raise your lifetime risk.
Risk factorVisceral fat is strongly associated with insulin resistance — the root driver of rising HbA1c.
Risk factorADA and USPSTF recommend HbA1c screening for all adults 35–70 who are overweight.
ScreeningTesting Schedule
Frequency depends on your current health status and your doctor's guidance.
No symptoms, normal weight, no family history. Standard annual preventive screening.
Every 6 months to monitor whether lifestyle changes are working before escalation.
Every 3 months when on medication with well-controlled, on-target results.
More frequent when starting insulin, changing doses, or after a significant lifestyle change.
If Your Result Is Abnormal
Prediabetes is genuinely reversible. These four levers have strong clinical evidence behind them.
Reducing refined carbohydrates directly lowers post-meal glucose spikes. A Mediterranean or low-GI diet shows consistent results in 3-month studies.
−0.5 to −1.0% HbA1c150 minutes per week of moderate activity — brisk walking, cycling, swimming — improves insulin sensitivity and glucose uptake in muscle tissue.
−0.4 to −0.7% HbA1cLosing just 5–10% of body weight significantly reduces insulin resistance, often enough to bring prediabetes back to normal without medication.
−0.3 to −0.8% HbA1cChronic sleep deprivation raises cortisol and disrupts insulin signalling. Improving sleep reduces HbA1c independently of diet.
Emerging evidenceClinician-reviewed articles published in this category — referenced, sourced, and written for patients and practitioners alike.
Article
Understand Type 2 Diabetes Biomarkers: A comprehensive review of their role in diagnosis, normal reference ranges, and implications of high and low…
