The haemoglobin A1c test, also called HbA1c, glycated haemoglobin test, or glycohaemoglobin - is an important blood test used to determine how well your diabetes is being controlled. Haemoglobin A1c provides an average of your blood sugar control over a six to 12 week period and is used in conjunction with home blood sugar monitoring to make adjustments in your diabetes medicines.
Haemoglobin is a substance within red blood cells that carries oxygen throughout your body. When your diabetes is not controlled (meaning that your blood sugar is too high), sugar builds up in your blood and combines with your haemoglobin, becoming glycated. Therefore, the average amount of sugar in your blood can be determined by measuring a haemoglobin A1c level. If your glucose levels have been high over recent weeks, your haemoglobin A1c test will be higher.
Hb A1C test is not used to diagnose diabetes, only used to monitor the control of diabetes.
In early phase of diabetes the blood sugars after meals (postprandial) start going up first while the fasting blood sugars are still normal. So I would recommend you to check blood sugars 2 hours after meals and get a glucose tolerance test done.