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Understanding A1C: Everything You Need to Know

PBTT

Private Blood Tests Team

Clinical Team

29 Dec 202410 min read

The A1C test, also known as HbA1c or glycated haemoglobin, is one of the most important blood tests for understanding your blood sugar control over time. Whether you are managing diabetes, at risk of developing it, or simply want to understand your metabolic health, the A1C test provides valuable insights that a single blood glucose reading cannot offer.

What is A1C?

A1C measures the percentage of haemoglobin in your red blood cells that has glucose attached to it. Haemoglobin is the protein in red blood cells that carries oxygen throughout your body. When glucose enters your bloodstream, some of it naturally binds to haemoglobin, creating what is called glycated haemoglobin.

The higher your blood glucose levels have been over the past two to three months, the more glucose will be attached to your haemoglobin. This is because red blood cells have a lifespan of approximately 120 days, so the A1C test reflects your average blood sugar levels over this period rather than just a snapshot in time.

This makes A1C particularly useful for understanding long-term blood sugar patterns, as it is not affected by day-to-day fluctuations or what you ate the night before.

Why is A1C Testing Important?

A1C testing serves several crucial purposes in healthcare:

Diagnosing Diabetes and Pre-diabetes

The A1C test is one of the primary tools for diagnosing type 2 diabetes and identifying people with pre-diabetes who are at high risk of developing the condition. Unlike fasting glucose tests, A1C does not require you to fast, making it more convenient for many patients.

Monitoring Diabetes Management

For people already diagnosed with diabetes, regular A1C testing helps assess how well their treatment plan is working. It shows whether blood sugar levels are being adequately controlled over time, allowing healthcare providers to adjust medications, diet, or lifestyle recommendations as needed.

Assessing Complication Risk

Research has shown a strong correlation between A1C levels and the risk of diabetes-related complications. Higher A1C levels increase the risk of:

  • Heart disease and stroke
  • Kidney disease (nephropathy)
  • Eye problems (retinopathy)
  • Nerve damage (neuropathy)
  • Poor wound healing
  • By monitoring and managing A1C levels, people with diabetes can significantly reduce their risk of these serious complications.

    Understanding A1C Results

    A1C results are expressed as a percentage. The interpretation is as follows:

    Normal: Below 5.7% (below 39 mmol/mol)

    This indicates healthy blood sugar control with no signs of diabetes or pre-diabetes.

    Pre-diabetes: 5.7% to 6.4% (39-47 mmol/mol)

    This range suggests impaired glucose regulation and increased risk of developing type 2 diabetes. Lifestyle changes at this stage can often prevent or delay the progression to diabetes.

    Diabetes: 6.5% or higher (48 mmol/mol or higher)

    An A1C at or above this level on two separate tests typically confirms a diabetes diagnosis.

    A1C Targets for People with Diabetes

    For most adults with diabetes, the general target A1C is below 7% (53 mmol/mol). However, targets may vary based on individual circumstances:

  • Younger patients with newly diagnosed diabetes may aim for tighter control (below 6.5%)
  • Older adults or those with other health conditions may have more relaxed targets (below 8%)
  • Pregnant women with diabetes have specific targets determined by their healthcare team
  • Your healthcare provider will help determine the most appropriate A1C target for your situation.

    The A1C Test Procedure

    One of the advantages of A1C testing is its simplicity. Here is what to expect:

    Preparation

    No fasting is required for an A1C test. You can eat and drink normally before your appointment, making it more convenient than fasting glucose tests. However, if your A1C is being performed alongside other blood tests that do require fasting, follow the specific preparation instructions provided.

    During the Test

    The A1C test requires a simple blood draw. A healthcare professional will collect a small blood sample from a vein in your arm. The procedure takes just a few minutes and causes minimal discomfort – typically just a brief pinch when the needle is inserted. For more details about what to expect during a blood test, read our comprehensive guide on blood testing procedures, results, and after effects.

    Getting Your Results

    Laboratory results are typically available within a few days. At Private Blood Tests London, we deliver your results securely and promptly. We provide raw data and recommend sharing your results with your GP or healthcare provider for interpretation and any necessary follow-up care.

    Factors That Can Affect A1C Results

    While A1C is generally reliable, certain factors can affect its accuracy:

    Conditions affecting red blood cells:

  • Anaemia (iron deficiency, vitamin B12 deficiency)
  • Haemoglobin variants (sickle cell disease, thalassemia)
  • Recent blood loss or blood transfusion
  • Chronic kidney disease
  • Certain medications
  • If you have any of these conditions, inform your healthcare provider, as alternative testing methods may be more appropriate.

    Other considerations:

  • Pregnancy can affect A1C interpretation
  • Age and ethnicity may slightly influence results
  • Recent illness or stress can temporarily affect blood sugar levels
  • How Often Should You Test A1C?

    Testing frequency depends on your health status:

  • People without diabetes: Testing every three years is generally recommended as part of routine health screening, or more frequently if you have risk factors
  • People with pre-diabetes: Annual testing helps monitor progression
  • People with well-controlled diabetes: Testing every six months may be sufficient
  • People with diabetes requiring treatment changes: Testing every three months helps assess the effectiveness of new interventions
  • For comprehensive diabetes monitoring, consider our health screening packages which include A1C alongside other important metabolic markers.

    Lowering Your A1C Naturally

    If your A1C is higher than desired, lifestyle modifications can make a significant difference:

    Dietary Changes

  • Reduce refined carbohydrates and added sugars
  • Choose whole grains over processed grains
  • Increase fibre intake through vegetables, legumes, and whole foods
  • Control portion sizes
  • Limit sugary drinks and fruit juices
  • Physical Activity

    Exercise helps your body use insulin more effectively. Aim for:

  • At least 150 minutes of moderate aerobic activity per week
  • Resistance training two to three times per week
  • Breaking up prolonged sitting with movement
  • Weight Management

    Even modest weight loss (5-10% of body weight) can significantly improve A1C levels in people who are overweight.

    Medication Adherence

    If you have been prescribed diabetes medications, taking them as directed is essential for achieving target A1C levels.

    Stress Management

    Chronic stress can raise blood sugar levels. Techniques like meditation, deep breathing, and adequate sleep can help.

    A1C vs. Blood Glucose Testing

    A1C and regular blood glucose testing serve complementary purposes:

  • A1C shows your average blood sugar over two to three months, ideal for assessing overall control
  • Fasting glucose provides a snapshot of blood sugar after not eating, useful for diagnosis
  • Self-monitoring (finger prick tests) shows real-time blood sugar, helpful for daily management decisions
  • For a complete picture of metabolic health, many healthcare providers use a combination of these tests.

    When to Seek Medical Advice

    At Private Blood Tests London, we provide your raw A1C data. We recommend consulting your GP or healthcare provider if:

  • Your A1C is in the pre-diabetes or diabetes range
  • You have symptoms of high blood sugar (increased thirst, frequent urination, fatigue, blurred vision)
  • You have risk factors for diabetes (family history, obesity, sedentary lifestyle)
  • You need guidance on interpreting your results or making lifestyle changes
  • Book Your A1C Test Today

    Understanding your A1C is a crucial step in managing your metabolic health. At Private Blood Tests London, we offer convenient A1C testing at our CQC-registered clinic in South Kensington. Our experienced team ensures a comfortable experience, and your results are delivered quickly and securely.

    Explore our [diabetes testing services](/diabetes-test), learn about [HOMA-IR for insulin resistance](/blog/homa-ir-explained-the-blood-test-that-detects-insulin-resistance-early), and see our [health screening packages](/health-screening).

    Whether you are monitoring existing diabetes, concerned about your risk, or simply want to understand your blood sugar control, book your A1C test today and take control of your health.

    Ready to Book Your Test?

    Visit our CQC-registered clinic in South Kensington for professional blood testing services.