The A1C is a test, which is used to measure the blood glucose level by assessing the amount of the glycated haemoglobin. It is also known as the haemoglobin A1C or HbA1C test.
The normal level of the A1c is below 5.7%, an HbA1C level between 5.7 and 6.4 shows the signals of prediabetic condition, if the A1C test shows sugar eve more than 6.5, the person is affected with diabetes.
Hence, Sarah should tell her that this test is done test, if you are diabetic or not. And, in case, you are not, you are prone to diabetes in near future or not.