UNDERSTANDING YOUR READINGS

Understanding Your HbA1c: What It Means and the Chart

One blood test, one number, roughly three months of history. Here is what it measures, the chart it maps to, and what to do with it.

4 min readSeptember 1, 2026

Purple-top blood collection tubes with barcode labels held in a gloved hand — Photo via AhmadArdity / Pixabay (opens in a new tab)

HbA1c — also written A1C, or sometimes just "glycated hemoglobin" on a Pakistani lab slip — is a single blood test that stands in for roughly three months of your blood sugar history. Unlike a fasting sugar test or a glucometer reading, which tell you what your glucose was at one moment, HbA1c is built to average out the noise of individual days and show the underlying trend.

What the test actually measures

Glucose circulating in your blood attaches to hemoglobin, the protein inside red blood cells that carries oxygen. Once glucose sticks to hemoglobin, it stays stuck for the life of that red blood cell — roughly 120 days. The HbA1c test measures what percentage of your total hemoglobin has glucose attached to it. The more glucose your blood has carried over recent months, the higher that percentage.

Because red blood cells are a mix of ages — some nearly new, some close to being replaced — the result leans toward the recent past rather than spreading evenly across three months. Roughly half of the HbA1c value reflects glucose exposure from the most recent month, with the two months before that contributing the rest. That is why an HbA1c can shift noticeably after four to six weeks of real change, even though it is often described as a "three-month average."

The HbA1c chart: normal, prediabetes, diabetes

The American Diabetes Association's Standards of Care in Diabetes—2026 (opens in a new tab) sets out the ranges used for diagnosis, and they are the numbers most Pakistani labs print on the reference-range column of your report.

HbA1c	Classification	Estimated average glucose (mg/dL)
Below 5.7%	Normal	Under 117
5.7% – 6.4%	Prediabetes	117 – 137
6.5% or higher	Diabetes (diagnostic range)	140 or higher
Below 7.0%	Common management target for many adults with diabetes	Roughly 154

A diagnosis usually needs more than one number

A single HbA1c in the diabetes range is normally confirmed with a repeat test, or alongside a fasting glucose or oral glucose tolerance test, unless someone already has clear symptoms of high blood sugar. Your doctor decides how to confirm a diagnosis — this chart is for understanding a report, not for self-diagnosing.

Turning the percentage into a glucose number

A percentage can be hard to relate to a glucometer reading in mg/dL, so labs and clinicians often convert HbA1c into an "estimated average glucose," or eAG. The conversion comes from the international ADAG study and is published by NGSP (opens in a new tab), the body that standardises HbA1c testing worldwide, as eAG (mg/dL) = (28.7 × HbA1c) − 46.7.

HbA1c	Estimated average glucose (mg/dL)
6%	126
7%	154
8%	183
9%	212
10%	240
11%	269
12%	298

Treat these as estimates, not exact translations. The relationship was fitted across a large group of people, so any one person's true average can sit a bit above or below the number the formula predicts. It is a useful way to sanity-check a lab result against your own glucometer log, not a substitute for either measurement.

How HbA1c relates to your daily readings

HbA1c and a glucometer reading are answering two different questions, so they are not meant to match exactly. Your meter tells you what your glucose is doing right now. HbA1c tells you what it has been doing, on average, for months — and an average, by its nature, cannot show you the highs and lows that produced it. Two people can share the same HbA1c while one runs steadily in range and the other swings between lows and spikes. If your own readings and your HbA1c seem to disagree, that is common enough to have its own explanation — see [why HbA1c is different from your glucometer reading](/blog/why-hba1c-is-different-from-glucometer-readings) for the fuller picture.

How often is it tested?

For most adults already diagnosed with diabetes, CDC guidance (opens in a new tab) suggests testing roughly every three to six months, depending on how stable your control is and whether your treatment has recently changed. If your HbA1c is in the prediabetes range, a repeat test every one to two years is a common schedule, though your doctor may test sooner if your risk factors warrant it.

Some things can throw the number off

Conditions that affect how long red blood cells survive — including certain anemias, kidney disease, and some inherited hemoglobin variants — can push HbA1c up or down without your actual glucose changing. This is common enough in Pakistan to be worth knowing about in detail; see [can anemia affect your HbA1c result](/blog/can-anemia-affect-hba1c-results).

“HbA1c is the summary. Your day-to-day readings are the detail that explains it.”

Give your next HbA1c some context

A logbook of your daily readings is what turns a single lab percentage into a pattern you and your doctor can actually work with.

Start logging with Diatic

Frequently asked questions

Do I need to fast for an HbA1c test?

No. HbA1c reflects months of glucose exposure rather than what you ate that morning, so you can have the sample taken at any time of day, fasted or not. Other tests ordered at the same visit, such as fasting glucose or a lipid profile, may still require fasting.

Is an HbA1c of 7% the same as a blood sugar of 154 mg/dL all day?

No. 154 mg/dL is an estimated average, not a flat line. Your actual glucose moves above and below that number throughout the day — after meals it may be considerably higher, and overnight or between meals it is usually lower.

What is a normal HbA1c for someone without diabetes?

Below 5.7% is the normal range used for diagnosis by the American Diabetes Association. Someone already living with diabetes typically has an individualized target, often below 7%, agreed with their doctor rather than aiming for the non-diabetic normal range.

Can my HbA1c change without my diabetes actually changing?

Yes. Lab-to-lab variation, the specific testing method used, and conditions affecting red blood cells such as anemia or kidney disease can all shift the number somewhat. A single small change is rarely meaningful on its own — a consistent trend across two or three tests is more informative than any one result.