Welcome back. His A1c levels have risen and this should be a concern for the doctor. A non-diabetic's A1c is in the 4's and 5's. Is he taking any medications that could affect his blood sugar?
Maybe the doctor suspects he could have type 1 diabetes? If so, there is the c-peptide test to check to see if the pancreas is producing insulin.
These lab results mean the doctor must follow up on them to make sure the tests are accurate and if your son needs more tests to find out what's going on. The lab tests for diabetes (A1c, c-peptide, fasting and the glucose tolerance test) are all done by taking blood. The GTT is done by taking blood, drinking a glucose drink and taking more blood usually an hour and maybe two hours later.
Make sure your doctor knows you're waiting for the next step because this should not be dropped. I hope he's doing ok. How does he feel?
Here are some sites with information:
/www.nlm.nih.gov/medlineplus/ency/article/003701.htmwww.mayoclinic.org/diseases-conditions/type-1-diabetes-in-children/basics/tests-diagnosis/con-20029197