What are the ideal Fasting Blood Sugar (FBS) and Post-Prandial Blood Sugar (PPBS) levels?

Ideal Blood Sugar Levels for FBS and PPBS

The ideal blood sugar targets are fasting blood glucose of 80-130 mg/dL (4.4-7.2 mmol/L) and post-prandial blood glucose of <180 mg/dL (10.0 mmol/L) measured 1-2 hours after the start of a meal. 1, 2

Target Blood Sugar Ranges

Fasting Blood Sugar (FBS)

• Target range: 80-130 mg/dL (4.4-7.2 mmol/L) 1, 2
• This represents the preprandial (before meal) glucose target recommended by the American Diabetes Association
• Values consistently ≥126 mg/dL (7.0 mmol/L) after at least 8 hours of fasting meet diagnostic criteria for diabetes 1

Post-Prandial Blood Sugar (PPBS)

• Target range: <180 mg/dL (10.0 mmol/L) measured 1-2 hours after the start of a meal 1, 2
• This timing is critical as it generally captures peak glucose levels in patients with diabetes
• Post-meal glucose monitoring is particularly important when A1C goals are not being met despite achieving target fasting glucose levels 1, 2

Special Populations

Pregnant Women

• More stringent targets are recommended:
  • For gestational diabetes: 1-hour postmeal ≤140 mg/dL or 2-hour postmeal ≤120 mg/dL 2
  • For pre-existing diabetes during pregnancy: peak postprandial glucose of 100-129 mg/dL 2
  • Fasting plasma glucose <95 mg/dL (5.3 mmol/L) 1

Clinical Significance of Blood Sugar Targets

Relationship to HbA1c

• The relative contribution of postprandial glucose to HbA1c is higher (approximately 70%) in patients with good glycemic control (HbA1c <7.3%) 3
• As glycemic control worsens (HbA1c >10.2%), the contribution of fasting glucose increases to about 70% 3
• Therefore, focusing on postprandial control becomes more important for patients who are closer to their HbA1c targets

Cardiovascular Risk

• Elevated postprandial glucose has been linked to increased cardiovascular risk independent of fasting glucose levels 1, 2, 4
• Even isolated postprandial hyperglycemia (2-hour postprandial glucose >140 mg/dL) with normal fasting glucose and normal HbA1c is associated with a 2-fold increased risk of cardiovascular mortality 4

Monitoring Recommendations

• For most adults with diabetes, checking blood glucose before meals and 1-2 hours after the start of meals provides the most useful information 1, 2
• The American Diabetes Association does not specify a mandatory frequency for type 2 diabetes, but recommends 3 or more times daily for type 1 diabetes 1
• Monitoring should be more frequent in people with:
  • Unstable glycemia
  • Risk of hypoglycemia
  • Recent treatment changes 1

Common Pitfalls to Avoid

1. Incorrect timing of postprandial measurements: Measure 1-2 hours from the start of the meal, not from the end 1, 2

2. Overlooking postprandial glucose: Many patients focus only on fasting levels but miss significant postprandial excursions that contribute to overall glycemic control 2

3. Not adjusting targets based on individual risk: Severe or frequent hypoglycemia is an absolute indication for modifying treatment regimens and setting higher glycemic goals 1

4. Ignoring diurnal variations: Glucose responses may be higher in the evening compared to morning, even with identical meals 2

By maintaining blood glucose levels within these target ranges, patients can significantly reduce their risk of both microvascular and macrovascular complications associated with diabetes.