Fasting Blood Glucose

 Fasting blood glucose or fasting blood sugar (FBS) levels are used to help diagnose diabetes mellitus and hypoglycemia. Glucose is a monosaccharide found in fruits and is formed from the digestion of carbohydrates and the conversion of glycogen by the liver. Glucose is the main source of cellular energy for the body and is essential for brain and erythrocyte function.

Normal Lab Value for Glucose

• Glucose, fasting: 70 – 110 mg/dL
• Glucose, monitoring: 60 – 110 mg/dL
• Glucose, 2-hr postprandial: < 140mg/dL

Nursing consideration:

• Instruct the client to fast for 8 to 12 hours before the test.
• Instruct a client with diabetes mellitus to withhold morning insulin or oral hypoglycemic medication until after the blood is drawn.