Thursday, June 1, 2023

Anaemias Cause Your Diabetes Test To Show Wrong Results

In medical situations that lead to alteration in the red blood cell population, the measured values of glycated haemoglobin differ from the actual values.


  • If anything other than your blood glucose changes blood haemoglobin, it leads to a glycated haemoglobin value that is not indicative of blood glucose control.
  • Iron deficiency anaemia, uncontrolled hypothyroidism, late-stage pregnancy, and blood loss can give rise to wrong glycated haemoglobin values.

The Science

What is Glycated Haemoglobin?

  • Glycated Hemoglobin, also known as HbA1c or A1c, test indicates your average blood glucose over the prior three months.
  • Since its value does not change with short-term blood glucose fluctuations, it is a good test to indicate your recent blood glucose control.
  • In the presence of blood glucose, the blood haemoglobin becomes glycated, which means it gets an added glucose molecule.
  • Higher blood glucose leads to more glycation. The longer the blood glucose is higher, the more is glycation. Thus, HbA1c measures how long and how much the blood glucose was high.
  • Since both the level and duration of high blood glucose determine diabetes-related organ damage, HbA1c is a good indicator of your blood glucose control.
  • Blood haemoglobin resides on your red blood cells. Since your red blood cells are recycled every three months, the glycated haemoglobin on them gets out of the blood circulation and is not measured.

Read more on this website: Glycated Hemoglobin: A Test to Measure Long-Term Blood Glucose Control.

When Glycated Haemoglobin Gives Wrong Results?

If anything other than blood glucose changes blood haemoglobin, it leads to a glycated haemoglobin value that is not indicative of blood glucose control.

  • Various anaemic conditions can show elevated HbA1c results compared to the actual values. In developing countries, iron deficiency anaemia is prevalent and the HbA1c values in such populations tend to be higher.
  • If you have uncontrolled hypothyroidism or hyperthyroidism, anaemic conditions prevail leading to a similar problem.
  • If you have vitamin B12 or vitamin B9 deficiency, the body cannot make new red blood cells properly. HbA1c values tend to be higher in such cases, as more blood cells are older.
  • In the late stages of pregnancy, there could be a shortfall of iron in the blood causing anaemia. In such cases, the HbA1c levels measured will be higher than the actual ones.
  • Since there is a medical condition called Gestational Diabetes, in which a pregnant woman develops diabetes, one must be careful in interpreting HbA1c values. They could be correctly higher due to diabetes or incorrectly elevated due to the anaemic status.
  • A blood loss or transfusion can change the red blood cell composition, altering the measured value of HbA1c.

All incorrect measurements revert to accurate values once the problems are corrected using medicines, food, or supplementation. My short video on this subject is below.

To read more

First published on: 3rd December 2021
Image credit: Marcus Aurelius on Pexels
Last Updated on: 27th May 2023


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