HbA1c

HbA1c is a key blood test that gives us a picture of your average blood sugar levels over the past two to three months. Think of it as a long-term report card for your blood glucose, rather than a snapshot of what it is right this second. It's considered the gold-standard marker for diagnosing and monitoring diabetes.

What it is

Your red blood cells contain a substance called haemoglobin, which is responsible for carrying oxygen around your body. When glucose (sugar) circulates in your bloodstream, some of it naturally attaches to this haemoglobin. The more glucose there is in your blood, the more glucose will attach to your haemoglobin.

HbA1c specifically measures the percentage of your haemoglobin that has glucose attached to it. This process happens slowly over time, which is why HbA1c reflects your average blood sugar levels over a period of about 8-12 weeks. The lifespan of a red blood cell is around 120 days, so the test gives a good indication of your blood sugar control during that time. The result is usually reported in millimoles per mole (mmol/mol).

Why it matters

Monitoring your HbA1c is crucial because consistently high blood sugar levels can lead to serious long-term health complications. Over time, excess glucose can damage blood vessels and nerves throughout your body. This can increase the risk of problems affecting your:

• Heart and circulation: Including heart attacks, strokes, and peripheral artery disease (poor circulation in the legs).
• Kidneys: Potentially leading to kidney disease or failure.
• Eyes: Causing damage to the retina (retinopathy), which can affect vision and even lead to blindness.
• Nerves: Resulting in nerve damage (neuropathy), which can cause pain, numbness, and tingling, particularly in the feet and hands.
• Feet: Increased susceptibility to infections and slow-healing wounds, which can sometimes lead to amputation.

By keeping your HbA1c within a target range, you can significantly reduce the risk of developing these complications. For individuals with diabetes, the target HbA1c level is usually around 48 mmol/mol or lower, but this can vary depending on individual circumstances, and your GP will discuss what's right for you.

What can cause it to be high or low

Higher than usual HbA1c levels can be associated with:

• Diabetes: This is the most common reason for elevated HbA1c.
• Pre-diabetes: Blood sugar levels are higher than normal but not yet high enough to be diagnosed as diabetes.
• Certain medical conditions: Such as an underactive thyroid (hypothyroidism) or kidney disease.
• Some medications: For example, steroids can raise blood sugar.
• Recent illness or stress: Short-term factors can temporarily increase blood sugar.

Lower than usual HbA1c levels can be associated with:

• Hypoglycaemia: Blood sugar levels that are too low. This can occur if someone with diabetes is taking certain medications and their blood sugar has dropped significantly.
• Certain medical conditions: Such as an overactive thyroid (hyperthyroidism), severe anaemia, or chronic blood loss.
• Pregnancy: Blood sugar levels often change during pregnancy.
• Certain genetic conditions: Affecting haemoglobin.

It's important to remember that a single HbA1c result is just one piece of the puzzle. Your GP will consider it alongside your medical history, other test results, and how you're feeling.

Lifestyle factors that may help

Making positive lifestyle changes can play a significant role in managing your blood sugar levels and potentially improving your HbA1c. These are all areas that can be beneficial to discuss with your healthcare team:

• Diet: Focusing on a balanced diet rich in fruits, vegetables, and whole grains, while limiting processed foods, sugary drinks, and excessive saturated fats, can help regulate blood glucose.
• Physical activity: Regular exercise, such as brisk walking, swimming, or cycling, can improve your body's sensitivity to insulin and help lower blood sugar levels.
• Weight management: If you are overweight, losing even a small amount of weight can have a positive impact on your blood sugar control.
• Smoking cessation: Smoking can worsen insulin resistance and increase the risk of diabetes complications. Stopping smoking is one of the best things you can do for your overall health.
• Alcohol consumption: Moderating alcohol intake is generally advised.

Questions to discuss with your GP

• What is my current HbA1c result, and what does it mean for me?
• What is the ideal HbA1c target range for my individual health situation?
• Are there any specific dietary changes you would recommend to help manage my blood sugar levels?
• What types and amounts of physical activity would be most beneficial for me?
• Are there any other tests or investigations that might be helpful alongside my HbA1c result?
• How often should I have my HbA1c levels checked?