In 2010, the National Center for Disease Control of China and the Chinese Medical Association Endocrinology Branch surveyed: the prevalence of diabetes in China is 9.7% in people over 18 years old. Once again, it is confirmed that China may have become the country with the largest number of people with diabetes in the world. For the initial diagnosis of diabetes, doctors need to ask detailed questions about the clinical symptoms of diabetes and its complications, understand the family history of diabetes, and perform some laboratory tests to determine the diagnosis and condition of the patient; during the follow-up consultation of the patient with diabetes, doctors need to review the patient’s previous treatment plan and glycemic control, and then perform some laboratory tests according to the patient’s condition to determine the patient’s individualized treatment goals. Today, we will talk about diabetes laboratory tests. Fasting blood glucose (FBG) is a common and important indicator for diagnosing glucose metabolism disorders, and refers to the blood glucose value measured after overnight fasting (fasting for at least 8-10h) and before breakfast. A fasting venous plasma glucose level < 6.1 mmol/L is considered normal, ≥ 7.0 mmol/L meets the diagnostic criteria for diabetes, while between 6.1 and 7.8 mmol/L is impaired fasting glucose (IFG), a form of impaired diabetes regulation (also called prediabetes). For patients with type 2 diabetes, it is generally recommended to control fasting blood glucose between 4.4 and 7.0 mmol/L. 2. Postprandial blood glucose (PBG) is also an important indicator for the diagnosis and control of diabetes. Generally, in normal people, blood glucose reaches its peak level 0.5~1 hour after meal, and returns to the pre-meal level in 2~3 hours. Doctors generally recommend patients to measure blood glucose 2 hours after meal. 2 hours after meal is the time from the first bite of food or the first 75g of glucose water. A venous plasma glucose level < 7.8 mmol/L 2 hours after a meal is considered normal, ≥ 11.1 mmol/L meets the diagnostic criteria for diabetes, and between 7.8 and 11.1 mmol/L is defined as impaired glucose tolerance (IGT), another form of impaired regulation of diabetes. For patients with type 2 diabetes, non-fasting glucose control below 10.0mmol/L is generally recommended.