HbA1c

HbA1c (glycated hemoglobin) is a form of hemoglobin that is measured primarily to determine the average plasma glucose concentration over prolonged periods. When glucose circulates in your blood, some of it naturally binds to hemoglobin — the protein in red blood cells that carries oxygen. The more glucose in your blood, the more hemoglobin gets glycated. Since red blood cells live for about 3 months, HbA1c reflects your average blood sugar over that period.

HbA1c is commonly tested to screen for diabetes and prediabetes, and to monitor how well blood sugar is being managed in people who have already been diagnosed with diabetes. Unlike a fasting glucose test, which shows your blood sugar at a single moment, HbA1c gives a longer-term picture and is not affected by short-term factors like recent meals or stress.

HbA1c is measured with a simple blood test, typically drawn from a vein in your arm. No fasting is required. The sample is analyzed in a laboratory to determine the percentage of hemoglobin that is glycated. Results are reported as a percentage.

A common reference range for HbA1c is below 5.7% for normal, 5.7-6.4% for prediabetes, and 6.5% or above for diabetes. However, reference ranges and diagnostic thresholds can vary between laboratories, professional guidelines, and populations. Always refer to the reference range provided by your laboratory and discuss your results with a qualified healthcare provider.

• Recent blood loss or transfusion
• Certain types of anemia
• Pregnancy
• Kidney or liver disease
• Ethnic background
• Age
• Certain medications

Frequently asked questions

• · American Diabetes Association. Standards of Medical Care in Diabetes.
• · World Health Organization. Use of Glycated Haemoglobin (HbA1c) in the Diagnosis of Diabetes Mellitus.