Why is it necessary to measure both fasting blood glucose and blood glucose two hours after a meal?

Generally, fasting blood glucose and 2-hour postprandial blood glucose need to be measured, possibly to reflect the basal glucose metabolism status, assess postprandial glucose regulation capacity, detect impaired glucose tolerance early, monitor the treatment effectiveness for diabetes, predict the risk of diabetic nephropathy, etc. If abnormal blood glucose is detected, timely consultation and treatment at a regular hospital are recommended. Detailed explanations are as follows:

1. Reflect Basal Glucose Metabolism Status

Fasting blood glucose reflects the liver's glucose output after an overnight fast and the regulation of blood glucose by basal insulin secretion, serving as the basis for determining whether glucose metabolism is normal.

2. Assess Postprandial Glucose Regulation Capacity

Two-hour postprandial blood glucose reflects whether insulin secretion after eating effectively controls elevated blood glucose levels, indicating the body's ability to metabolize carbohydrates.

3. Early Detection of Impaired Glucose Tolerance

In some individuals, fasting blood glucose may be normal while postprandial blood glucose already exceeds the normal range, indicating impaired glucose tolerance, which is a precursor signal of diabetes. Daily total calorie intake should be controlled, and 150 minutes of moderate-intensity exercise per week is recommended.

4. Monitor Diabetes Treatment Effectiveness

Diabetic patients can determine whether basal medication is appropriate by measuring fasting blood glucose, and assess the effect of prandial insulin or hypoglycemic agents by measuring postprandial blood glucose. Combining both measurements comprehensively reflects the effectiveness of the treatment plan.

5. Predict Risk of Diabetic Nephropathy

Chronically elevated fasting or postprandial blood glucose can damage renal microvasculature and is a significant contributing factor to diabetic nephropathy. Keeping fasting blood glucose controlled between 4.4-7.0 mmol/L and 2-hour postprandial blood glucose below 10.0 mmol/L can reduce the risk of kidney damage.

In daily life, maintaining regular meal times and avoiding overeating are important. Choosing low glycemic index foods such as oats and legumes, engaging in moderate physical activity, managing body weight, and for diabetic patients, regularly monitoring blood glucose levels to adjust treatment plans according to results are essential to prevent complications.