An HbA1c between 5.7% and 6.4% indicates prediabetes; below 5.7% is normal and from 6.5% onward one speaks of type 2 diabetes. The test has limitations in cases of anemia, kidney problems, and pregnancy. A diagnosis always requires a repeated measurement by a doctor.
The HbA1c test tells you what your average blood sugar has been over the past two to three months. That makes it far more stable than a fasting blood glucose measurement, which fluctuates considerably depending on what you ate the day before. You can request it through your general practitioner as a standard blood draw, and it is covered by insurance when there is a medical indication.
What the result means: below 5.7% (39 mmol/mol) is considered normal, 5.7 to 6.4% points to prediabetes, and from 6.5% (48 mmol/mol) onward the term type 2 diabetes is used. These thresholds are international agreements, not sharp biological cut-off points, so a value just below or just above a threshold says less than a value that lies far from it.
One caveat that truly matters: the test can give a distorted picture in cases of anaemia, certain haemoglobin variants, kidney problems or pregnancy. It is also not the most sensitive instrument for detecting early blood sugar problems -- a glucose tolerance test picks those up more reliably. So if your result is normal but you have symptoms that concern you, it is worthwhile to discuss that with your general practitioner. Any diagnosis is always made by the doctor on the basis of a repeated measurement, never on a single test result alone.
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