What A1C Shows in Prediabetes

The A1C test is a simple blood draw. You do not need to fast first. It measures how much sugar sticks to your red blood cells.

Red blood cells live about two to three months. So the result shows your average blood sugar over that time.

Think of it as a three-month report card, not a single day's grade.

Red blood cells float in a blood vessel. With lower blood sugar only a little sugar sticks to them, and with higher blood sugar more sugar sticks to every cell. A cell then moves along a strip in three parts to show it lives for months.

A1C results fall into three ranges. Below 5.7% is normal.

5.7% to 6.4% is the prediabetes range. It is an early chance to act and make a plan.

6.5% or higher is in the diabetes range. A doctor usually repeats the test to confirm it before making a diagnosis.

Your doctor reads your A1C with your health history and other tests, then explains it.

Some conditions can make the A1C misleading. Iron-deficiency anemia, which means low iron, is one example. Kidney disease, where the kidneys do not clean the blood well, is another.

Key takeaways

• A1C shows your average blood sugar over about two to three months.
• The prediabetes range is 5.7% to 6.4%.
• A result of 6.5% or higher usually needs a repeat test before a diagnosis.

Try it

Find your most recent A1C number and its test date on a lab report or patient portal. Write both down, then see which of the three ranges from this lesson it sits in. If you have not had one yet, skip this step.