No, it is not that concerning. It falls under the category of prediabetes and with lifestyle changes it can be reversed.
Diabetes is a condition which is characterised by blood glucose levels which are more than normal.A blood sugar level less than 140 mg/dL (7.8 mmol/L) is normal. A reading of more than 200 mg/dL (11.1 mmol/L) after two hours means you have diabetes
280mg/dl is considered in the category of diabetes consult with a doctor immediately.
Yes if your result is 85 mg/dl then you surely dont fall under the diabetes category.