HbA1c and type 2 diabetes: what the test means

What the test measures

Glucose in your blood attaches to haemoglobin, the protein in red blood cells. An HbA1c test measures the percentage of haemoglobin with glucose attached. Red blood cells live for about three months, which is why the test gives a picture of the past two to three months rather than a single moment.

WHO notes that the test can be done at any time of day and does not need special preparation such as fasting. Those are practical advantages over some glucose tests.

What a result means

In a 2011 report, a WHO consultation concluded that HbA1c can be used to diagnose diabetes, provided strict quality checks are in place, the test is properly standardised, and no condition is present that stops it being measured accurately. It recommends 6.5% as the cut point.

WHO adds three points that are easy to miss:

• A value below 6.5% does not rule out diabetes found using glucose tests.
• If you have no symptoms, a single abnormal HbA1c or glucose result is not enough. At least one more test in the diabetic range is needed.
• WHO found too little evidence to make a formal recommendation on what levels below 6.5% mean.

You may see other ranges on a report or online. MedlinePlus, a US National Library of Medicine service, describes below 5.7% as normal, 5.7% to 6.4% as prediabetes and 6.5% or higher as diabetes. It also says these ranges are a guide and that what is normal depends on your health and age. Your lab report may use its own ranges, so ask your doctor what yours means for you.

What can affect the result

HbA1c is useful, but it is not right for everyone. WHO says the most common factors worldwide are inherited haemoglobin disorders, certain anaemias, and conditions that speed up the turnover of red blood cells, such as malaria. MedlinePlus also lists pregnancy, kidney failure, liver disease and some medicines.

It is not used to diagnose gestational diabetes or type 1 diabetes. Tell your doctor about your health conditions and all your medicines. Do not stop any medicine because of a test unless your doctor tells you to.

Why it matters for type 2 diabetes

WHO says type 2 diabetes accounts for more than 95% of people with diabetes. In type 2, the body cannot use insulin properly. Symptoms can be mild and may take years to appear, so some people are diagnosed only after complications have started. Over time, diabetes can damage the blood vessels in the heart, eyes and kidneys, as well as the nerves.

Common signs include intense thirst, passing urine often, blurred vision, tiredness and weight loss you did not plan. If you notice these, or you are worried about your risk, ask a doctor about testing. WHO says regular check-ups and blood tests are the best way to find diabetes early.

WHO describes a healthy lifestyle as one of the most important treatments, and some people with type 2 also need medicines. What is right for you is a decision to make with your doctor.

When to get urgent help

Call 998 or go to an emergency department for trouble breathing, fainting, sudden confusion, or vomiting that does not stop, whether or not you have diabetes.

For anything that is not urgent, you can search the medicAI lab test list by name, or by what a test measures. A licensed partner laboratory collects your sample and your results come back to the app. You can then talk them through with a doctor by video.