Fasting blood glucose and postprandial blood glucose are two key indicators in the diagnosis and daily management of diabetes. The difference between the two is mainly reflected in the measurement time, clinical significance and influencing factors. Fasting blood glucose reflects basal insulin secretion capacity, while postprandial blood glucose assesses postprandial insulin regulation. This article will focus on the definition, normal range, detection significance and management methods to help readers understand the differences between the two.

fasting blood glucoseRefers to the blood sugar value measured after not eating for at least 8 hours, and is usually used as the first choice indicator for diabetes screening. The normal value should be lower than 6.1mmol/L (WHO standard). If it is ≥7.0mmol/L, diabetes can be diagnosed. Its advantage is high stability, but it may miss patients with early-stage islet function impairment. For example, some patients have normal fasting blood sugar, but have significantly elevated blood sugar after meals. This situation is common in prediabetes.

postprandial blood sugarThe time starts from the first bite of food and is measured after 2 hours. The normal value should be less than 7.8mmol/L, and diabetes can be diagnosed when ≥11.1mmol/L. It more sensitively reflects abnormal glucose tolerance, and has more reference value especially for East Asian populations (such as China), because pancreatic β-cell function declines earlier in this population. For example, a study by Peking Union Medical College Hospital found that about 30% of people with normal fasting blood sugar have postprandial hyperglycemia.

Clinical management requires combined monitoring of both. For example, metformin (produced by Glucophage and other manufacturers) mainly reduces fasting blood sugar, while acarbose (Bai Tangping, etc.) focuses on controlling postprandial blood sugar. It is recommended that patients with diabetes measure fasting and postprandial blood glucose at least once a week. Dynamic observation such as Abbott's instant blood glucose meter can provide a more complete curve. In terms of diet, low GI foods such as oats (Quaker and other brands) can help stabilize blood sugar after meals.

(Reference materials: "Guidelines for the Prevention and Treatment of Type 2 Diabetes in China" by the Diabetes Branch of the Chinese Medical Association, WHO Blood Glucose Standards, and "Clinical Research on Postprandial Blood Glucose" by Peking Union Medical College Hospital)