Why 3 Months Matters

A blood sugar check shows your level at one moment. The A1C is a different kind of test. It shows your average blood sugar over about the last 3 months.

Think of it like a report card for a whole season, not one day. The A1C works that way too. It cannot show one meal, because it looks back about 3 months.

A chart shows a blood sugar line that rises and falls in three even hills across about 3 months, with ticks numbered 1, 2 and 3 under an axis titled Months. One check: the line is grey and one red dot marks a single moment, labelled One moment. About 3 months: the line is drawn across all three months, then a thin green band slides across at its middle height, labelled A1C average above its right end. New habits: the line slopes down over the months, and the A1C average band sits lower than before, below a dashed outline where it used to be, with an arrow pointing down and the label New habits.

That is why many people have their next A1C about 3 months after diagnosis. By then, new habits have had time to show up.

The American Diabetes Association (ADA) is a diabetes group. It suggests an A1C test at least twice a year. When treatment changes or goals are not met, it suggests every 3 months. Ask your care team how often you should test.

A slider moves between two schedules: every 3 months while goals are not met, and every 6 months once they are.

Key takeaways

• The A1C test looks back about 3 months.
• Many people have their next A1C about 3 months after diagnosis.
• Your care team sets your own test schedule and goals.

Try it

Find out when your next A1C test is due, and write that date on your calendar.