What are the differences between FBS and HbA1c testing?

A blood sugar test measures the blood sugar level to assess how well your body can control the blood sugar levels. This test can screen and identify people at risk of diabetes. Tracking blood sugars over time helps to evaluate the effectiveness of diabetes treatment. There are two blood tests for this purpose:

• Fasting Blood Sugar (FBS) requires at least 8 hours of fasting. The results reflect the blood sugar level at the time of the blood drawing. It is a standardized measurement that allows comparison among people on how well they can control their blood sugar.
  
  
• Glycated hemoglobin (HbA1c) measures the concentration of glycated hemoglobin proteins. It reflects the average blood sugar concentration over the past 2-3 months. The type and quantity of foods consumed significantly affect HbA1c level. This test can diagnose and help the management of diabetes and predict the risk of complications. Fasting is not necessary.

People can game the FBS blood testing for a spuriously better result by altering their food intakes a few days before the test. However, short-term diet manipulation cannot influence the HbA1c values.