HbA1c Test (Glycated Haemoglobin) for the Diagnosis of Diabetes

Context

The haemoglobin A1C (HbA1C) test is widely used for prevention and early detection of non-communicable diseases, including diabetes (both type 1 and type 2).

About HbA1C Test

• The HbA1C test is also known as the glycated haemoglobin or glycosylated haemoglobin test.
• Food contains sugar, which enters the bloodstream.
  • This sugar sticks to a protein called hemoglobin in your red blood cells. 
    • Hemoglobin’s job is to carry oxygen to all parts of your body. 
• The HbA1C test measures the percentage of red blood cells with sugar-coated hemoglobin.
  • It indicates the average blood sugar level over the past few months.
    • Higher levels suggest poor blood sugar control, while lower levels indicate better control.

HbA1C Measurement Units and Interpretation

• Percentage vs. mmol/mol: HbA1C levels can be reported either as a percentage or in mmol/mol (millimoles per mole).
• Interpretation by Percentage: Higher percentages indicate higher blood glucose levels. 
  • Normal levels are below 5.7%. 
  • Pre-diabetes is indicated between 5.7% and 6.4%.
  • 6.5% or higher may suggest diabetes.
• Interpretation by mmol/mol: Below 42 mmol/mol corresponds to below 6.0%. 
  • Levels between 42-47 mmol/mol indicate 6.0% to 6.4%, and 48 mmol/mol or higher corresponds to 6.5% or over.

Factors Affecting HbA1C Test Results

• Medical Conditions: Certain medical conditions such as kidney or liver failure, severe anaemia, or blood disorders like thalassemia can impact HbA1C results.
• Variations in Haemoglobin Types: Less common types of haemoglobin found in certain populations can affect HbA1C test outcomes.
• Medications: Use of medications including steroids, opiates, or dapsone (used to treat leprosy) can alter HbA1C readings.
• Pregnancy: HbA1C levels may change during early or late pregnancy.

Limitations of the HbA1C Test

• Complementary Testing Requirement: The HbA1C test does  not replace other tests for diabetes diagnosis and monitoring.
• Inaccurate result : Blood sugar levels can go up and down during the day and night, and the HbA1C test might not catch these changes.
• Variability in Acceptance:  While the HbA1C test is effective for assessing long-term diabetes control, it is not universally accepted as a diagnostic tool by all medical bodies globally because it gives  inconsistent results due to varying standards.

Diabetes and Pre-Diabetes Statistics in India

• Diabetes Prevalence in India:

  • Estimated Numbers: According to a nationwide study in 2023, India has approximately 101.3 million individuals diagnosed with diabetes.
  • Pre-Diabetes Population: Additionally, there are around 136 million individuals classified as pre-diabetic in the country.

• Associated Health Conditions:

  • Hypertension Rates: Over 35% of Indians suffer from high blood pressure.
  • Abdominal Obesity: Nearly 40% of the population has abdominal obesity.
    • Risk Factors for Diabetes: Both hypertension and abdominal obesity are significant risk factors for developing diabetes.

• Global Impact:

  • Diabetes Burden: India accounts for 17% of the total global diabetes patient population.

News Source: Thehindu

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