Home Biomarkers HbA1c (Glycosylated Haemoglobin)

HbA1c (Glycosylated Haemoglobin)

Diabetes Biomarker

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Collection Type: Blood

Body System

Related System: Diabetes

Overview

HbA1c (glycosylated haemoglobin) is haemoglobin with glucose irreversibly attached; the test measures the percent of haemoglobin that is glycated and reflects average blood glucose over the prior 8–12 weeks. It is used to detect and monitor diabetes mellitus and to assess long‑term glycaemic control. Symptoms prompting testing include increased thirst, frequent urination, unexplained weight loss, fatigue, blurred vision or frequent infections. Results can vary with age, ethnicity, pregnancy, kidney or liver disease, haemoglobin variants, anaemia, recent transfusion, and conditions that change red blood cell lifespan.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: Diabetes - Symptoms: polyuria, polydipsia, unexplained weight loss, fatigue, recurrent infections, blurred vision - Used to diagnose/monitor: prediabetes and diabetes, and to follow glycaemic control in known diabetics - Abnormal reasons: chronic hyperglycaemia, steroid use, endocrine disorders (↑); haemolysis, recent transfusion, shortened RBC lifespan (↓) - Lifestyle: poor diet, physical inactivity, obesity, smoking - Family history of type 2 diabetes increases need for testing

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Understanding Test Results

<4.0% (<20 mmol/mol): uncommon; may reflect shortened RBC lifespan (haemolysis, recent bleeding/transfusion) or some lab interference.
Not usually clinically concerning alone.
4.0–5.6% (20–38 mmol/mol): normal, low risk of diabetes.
5.7–6.4% (39–46 mmol/mol): indicates prediabetes increased risk of developing diabetes; lifestyle interventions recommended.
≥6.5% (≥48 mmol/mol) on two separate samples: diagnostic of diabetes.
In people with diagnosed diabetes: many targets aim for <7.0% (<53 mmol/mol) but targets are individualized (e.g., <6.5% for some, <8.0% for frail/older patients).
False elevations may occur with iron deficiency or certain assay interferences; false lows with haemolysis, recent transfusion, or some haemoglobinopathies.
Abnormal results warrant confirmation and clinical correlation with glucose measurements and patient context.

Normal Range

4.0-5.6% OR 20-38 mmol/mol

FAQs

Q: What is HbA1c normal level?

A: HbA1c reflects average blood glucose over 2–3 months. A normal (non‑diabetic) HbA1c is below 5.7%. Values of 5.7–6.4% indicate prediabetes, and ≥6.5% on two separate tests indicates diabetes. For people with diagnosed diabetes, individualized targets are often around <7% for many adults but may be adjusted higher or lower based on age and overall health.

Q: What is the HbA1c test in pregnancy?

A: The HbA1c test in pregnancy is a blood test that measures glycated hemoglobin, reflecting average blood glucose over the previous two to three months. It is used early in pregnancy to detect previously undiagnosed diabetes or poor preconception control, helps distinguish pre-existing diabetes from gestational diabetes, and guides monitoring and treatment to reduce risks to mother and baby.

Q: What does it mean when your glycosylated hemoglobin HbA1c is high?

A: A high HbA1c means your average blood glucose has been elevated over the past two to three months. It indicates poor diabetes control or undiagnosed diabetes and signals higher risk of complications such as heart disease, kidney damage, nerve injury, and vision problems. Management usually requires lifestyle changes, closer glucose monitoring, and possible medication or insulin adjustments under medical supervision.

Q: What is an alarming HbA1c level?

A: An alarming HbA1c is generally ≥8%—indicating poor glucose control and higher complication risk; levels ≥9–10% are especially concerning and typically require urgent treatment review. Diabetes is diagnosed at ≥6.5% (5.7–6.4% is prediabetes), and many targets aim for <7%. If your HbA1c is repeatedly above target, contact your healthcare team promptly.

Q: How to reduce HbA1c quickly?

A: To lower HbA1c faster: follow prescribed diabetes medications and review therapy with your clinician; cut refined carbohydrates and sugars, favor fiber and low‑GI foods; increase physical activity (aerobic resistance; aim for ~150 min/week); lose excess weight; monitor glucose regularly and adjust treatment with your team; limit alcohol, stop smoking, and manage stress and sleep. Rapid changes require medical supervision.

Q: Can HbA1c be high without diabetes?

A: Yes. HbA1c reflects average blood glucose over about three months but can be high without diabetes. Causes include prediabetes or transient hyperglycemia (illness, steroids), conditions affecting red blood cells or hemoglobin (iron‑deficiency anemia, hemoglobin variants, recent transfusion), chronic kidney or liver disease, alcohol misuse and some drugs. Abnormal A1c should be confirmed with repeat testing and/or direct glucose tests and clinical review.