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Evidence to Improve Care

Hemoglobin A1c Testing in Diabetes


Ontario Health Technology Advisory Committee Recommendations

  • The Ontario Health Technology Advisory Committee recommends that adult patients with diabetes (without hematologic contraindication) have hemoglobin A1c tested every three months if glycemic targets (generally hemoglobin A1c < 7%) are not met, or every six months if glycemic targets are being met.

  • The Ontario Health Technology Advisory Committee recommends that hemoglobin A1c should not be tested more than four times per year in adult patients with diabetes.

Read the full OHTAC Recommendation report



More than 90% of people with diabetes have type 2 diabetes. In 2011 – 2012, more than 3.4 million hemoglobin A1c tests were performed in adults older than 18 years of age in Ontario’s community laboratories. The number of tests had increased by 55% from 2.2 million tests in 2007 – 2008.


Health Quality Ontario Reviews Hemoglobin A1c Testing in Diabetes

Hemoglobin A1c has been widely used to check how well blood sugar is controlled. The value of hemoglobin A1c closely follows the concentration of blood glucose. In general, hemoglobin A1c reflects the average concentration of blood glucose over the preceding three months. Doctors use test results to decide on treatment, such as improving diet, increasing exercise and using drugs.

Ideal control of blood glucose has been shown to reduce the risk of other problems related to diabetes. According to the United Kingdom Prospective Diabetes Study, each 1% reduction in hemoglobin A1c reduced the risk of problems in small blood vessels by 25% in patients with type 2 diabetes.


Hemoglobin A1c Testing in Diabetes: A Rapid Review (PDF)
July 2014


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The Ministry of Health and Long-Term Care endorses this recommendation.

The Ministry of Health and Long-Term Care has provided the following response: The Ministry agrees with this recommendation and encourages health care professionals to adhere to it.



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