Home / Health / Diabetes Test Misleading? Variants Affect HbA1c Accuracy
Diabetes Test Misleading? Variants Affect HbA1c Accuracy
12 Nov
Summary
- HbA1c tests can be inaccurate due to haemoglobin variants.
- Iron deficiency anemia also falsely elevates HbA1c readings.
- Alternative tests like OGTT and fructosamine exist for accuracy.
HbA1c testing, commonly used for diabetes diagnosis, may yield inaccurate results due to factors like iron deficiency anemia and inherited haemoglobin variants. These conditions can artificially inflate or deflate HbA1c readings, potentially misclassifying individuals as diabetic or prediabetic, or overlooking existing blood sugar issues.
Haemoglobin variants, such as HbE, HbD-Punjab, and HbS, are prevalent in various Indian populations. These structural changes in haemoglobin can interfere with laboratory measurement methods or alter red blood cell lifespan, compromising the reliability of HbA1c results.
High-Performance Liquid Chromatography (HPLC) is a key method for HbA1c estimation, capable of detecting abnormal haemoglobin patterns. However, careful examination of the HPLC chromatogram by a pathologist is crucial to identify any interfering variants.
Iron deficiency anemia, common in India, can also lead to falsely elevated HbA1c levels. Conversely, conditions shortening red blood cell survival may cause falsely low readings. In such cases, doctors may recommend additional tests.
When HbA1c accuracy is compromised, alternative diagnostic tools include fasting plasma glucose and the Oral Glucose Tolerance Test (OGTT). The fructosamine test, reflecting blood sugar over two to three weeks, serves as a useful monitoring tool when HbA1c is unreliable.
It is important for individuals to understand that a normal HbA1c does not always rule out diabetes, especially if symptoms persist. Similarly, high readings warrant further investigation in the presence of anemia or haemoglobin variants.
