我不是医生，但是google 一下不难。

What is A1C? 

A1C, also known as hemoglobin A1c or HbA1c, is a blood test that measures the average blood sugar level over the past 2-3 months. It is a key indicator for diagnosing and managing diabetes. 

How is A1C Measured? 

During an A1C test, a small amount of blood is taken and analyzed. The test measures the percentage of hemoglobin in red blood cells that is bound to glucose (sugar). 

Interpretation of A1C Levels:

Normal: Less than 5.7%

Prediabetes: 5.7-6.4%

Diabetes: 6.5% or higher