Glycated Hemoglobin (HbA1c)

Overview

Glycated hemoglobin (HbA1c) is a form of hemoglobin chemically linked to glucose, reflecting the average blood sugar levels over the past two to three months. It plays a crucial role in monitoring long-term glucose control, especially in people with diabetes. Tracking HbA1c helps assess the risk of diabetes-related complications and guides treatment decisions to maintain optimal blood sugar levels.¹²

Scientific Background

HbA1c forms through a non-enzymatic glycation process where glucose molecules bind to hemoglobin in red blood cells. Since red blood cells have a lifespan of about three to four months, HbA1c levels represent an integrated measure of blood glucose over this period. The higher the blood glucose concentration, the greater the percentage of glycated hemoglobin. This biomarker correlates with the risk of diabetes complications such as cardiovascular disease, nephropathy, neuropathy, and retinopathy. HbA1c is closely related to other glucose markers but provides a more stable long-term overview compared to daily glucose measurements.²⁴

Measurement and Testing

HbA1c is measured via a blood test, typically using methods like high-performance liquid chromatography (HPLC) or immunoassays. The test does not require fasting and reflects average glucose levels over the previous 8 to 12 weeks. Factors such as anemia, kidney or liver disease, certain blood disorders (e.g., sickle cell anemia), medications, blood transfusions, and pregnancy can affect test accuracy. It is recommended to test HbA1c at least twice a year in people with stable glucose control and more frequently if treatment changes or glycemic control is poor.¹⁵

Reference Ranges

Standard HbA1c reference ranges for adults are:

• Normal: below 5.7%
• Prediabetes: 5.7% to 6.4%
• Diabetes: 6.5% or above

For most adults with diabetes, the treatment goal is to maintain HbA1c below 7%, though individual targets may vary based on age, comorbidities, and risk factors. These ranges are consistent across most demographics but may require adjustment in specific populations or clinical contexts.¹³

High Values

Elevated HbA1c levels indicate chronic hyperglycemia and poor blood sugar control. Causes include uncontrolled diabetes mellitus, insulin resistance, and certain endocrine disorders. High HbA1c is associated with increased risk of microvascular complications (retinopathy, nephropathy, neuropathy) and macrovascular diseases (heart attack, stroke). Symptoms related to high blood sugar may include increased thirst, frequent urination, fatigue, and blurred vision. Persistently high HbA1c levels necessitate medical intervention to reduce complication risks.²¹

Low Values

Low HbA1c levels are less common and may result from conditions such as hemolytic anemia, recent blood loss, or chronic kidney or liver disease, which reduce red blood cell lifespan. Excessively low HbA1c may also reflect hypoglycemia or overtreatment of diabetes. Symptoms can include dizziness, sweating, confusion, and weakness. Interpretation of low HbA1c should consider clinical context and potential interfering factors.¹

Improving Biomarker Levels

Improving HbA1c involves lifestyle modifications such as adopting a balanced diet low in simple sugars, engaging in regular physical activity, and maintaining a healthy weight. For people with diabetes, adherence to prescribed medications including insulin or oral hypoglycemics is essential. Monitoring and adjusting treatment plans with healthcare providers can optimize glycemic control. Some supplements may support glucose metabolism, but these should be used under medical supervision.¹³

Importance of Tracking

Regular monitoring of HbA1c provides valuable insight into long-term glucose control, enabling timely adjustments in therapy to prevent or delay diabetes complications. It supports personalized treatment goals and helps assess the effectiveness of lifestyle and pharmacological interventions. Tracking HbA1c is a cornerstone in diabetes management and risk stratification.¹²

Disclaimer

The information provided in this document is for educational purposes only and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.