Why HbA1c Can Lie About Blood Sugar
The influence of shorter red blood cell lifespan on the rate of HbA1c target achieved in type 2 diabetes patients with a HbA1c detection value lower than 7%
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
HbA1c may underestimate blood sugar in nearly 1 out of 3 patients with good test results
Doctors and patients trust HbA1c as the gold standard for diabetes control. This shows it can be misleading even when results look ideal.
Practical Takeaways
If your HbA1c is good but you feel symptoms of high blood sugar, ask your doctor about continuous glucose monitoring (CGM) or checking glycosylated albumin.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
HbA1c may underestimate blood sugar in nearly 1 out of 3 patients with good test results
Doctors and patients trust HbA1c as the gold standard for diabetes control. This shows it can be misleading even when results look ideal.
Practical Takeaways
If your HbA1c is good but you feel symptoms of high blood sugar, ask your doctor about continuous glucose monitoring (CGM) or checking glycosylated albumin.
Publication
Journal
Journal of Diabetes
Year
2022
Authors
Jun-ming Wang, L. Zhang, Yunru Bai, Xinli Wang, Weilin Wang, Jing Li, Saijun Zhou
Related Content
Claims (6)
Your HbA1c number isn't just about your average blood sugar — it also depends on how long your red blood cells live. The longer they stick around, the more sugar builds up on them, which can raise your HbA1c even if your blood sugar is stable.
In people with type 2 diabetes, red blood cells don’t live as long when there’s a bigger mismatch between their actual HbA1c levels and what those levels should be based on blood sugar — meaning the body’s sugar coating on blood cells doesn’t always match up with sugar levels.
If someone with type 2 diabetes has good HbA1c numbers but their red blood cells don’t live as long, their blood sugar might actually be higher than the test shows — meaning the test could be giving them a too-rosy picture of their sugar control.
Some people with diabetes might seem to have good blood sugar control based on standard tests, but if their red blood cells don’t live as long, the test could be misleading — and nearly 1 in 3 of these patients might actually have worse blood sugar levels than the test shows.
Even when blood sugar averages look good on a diabetes test, people with shorter-lived red blood cells might still have higher actual sugar levels throughout the day.