A fasting blood sugar (FBS) level is the result of a blood sample taken after a patient fasts for at least eight hours. A normal fasting blood sugar level for someone without diabetes is less than 100 mg/dL, or HbA1C below 5.7%.

Prediabetes is a fasting blood sugar level from 100 to 125 mg/dL, or HbA1C of 5.7%-6.4%. Diabetes is a fasting blood sugar level of 126 mg/dL and above, or HbA1C of 6.5% or higher.

Source:

https://www.mayoclinic.org