A1C & You - About A1C

A1C and Blood Sugar

How is an A1C test different than a blood sugar test?

Monitoring your blood glucose is also very important. A blood sugar test that you conduct at home with a meter tells you how much sugar is in your blood at that moment. Research studies show that improving blood sugar levels benefits patients with diabetes. The blood sugar reading on your meter reading is given in milligrams per deciliter (mg/dl) or millimoles per liter (mmol/L), depending on what country you live in.

Using a meter to measure your blood glucose can help you see how food, activity, and medicines affect your blood sugar. Knowing your blood sugar level can help you manage your diabetes day by day or even hour by hour. The blood sugar readings tell you when your blood sugar is too low or too high, so you can work with your health care provider to change your treatment plan.

Both testing your blood sugar at home and getting an A1C test are important for someone with diabetes. These tests tell a patient and his or her health care provider whether blood sugar is under control or if a treatment adjustment is necessary.

How Does A1C Relate to Blood Sugar Levels?

A strong relationship exists between A1C and blood sugar. An increase in A1C equates to an increase in blood sugar.[1] The table below shows the range or blood glucose that corresponds to an A1C value. The relationship between blood sugar levels and A1C was calculated through both Continuous Glucose Monitoring (CGM) and testing blood sugar 7 or 8 times per day.[2]

A1C Value (%) Blood Sugar Level (mg/dl) Blood Sugar Level (mmol/l)
5 97 (76-120) 5.4 (4.2-6.7)
6 126 (100-152) 7.0 (5.5-8.5)
7 154 (123-185) 8.6 (6.8-10.3)
8 183 (147-217) 10.2 (8.1-12.1)
9 212 (170-249) 11.8 (9.4-13.9)
10 240 (193-282) 13.4 (10.7-15.7)
11 269 (217 – 314) 14.9 (12.0 – 17.5)
12 298 (240-347) 16.5 (13.3 – 19.3)

Data in parentheses are 95% Confidence Intervals.
To convert (mmol/mol) A1C units (IFCC traceable) to (%)A1C (DCCT traceable) use the following equation(%A1C=(0.0915*A1C mmol/mol) + 2.15.

  1. Nathan et. al. "Management of Hyperglycemia in Type 2 Diabetes: A Consensus Algorithm for Initiation and Adjustment to Therapy", Diabetes Care 2006, 29 (8), pp. 1963-1973.
  2. Nathan, DM, Kuenen, Borg, R, Zheng, H, Schoenfeld, D, Heine, RJ. "Translating the A1C Assay Into Estimated Average Glucose Values" Diabetes Care Volume 32 (8), August 2008.
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