There are two main methods to check blood glucose, one is fingertip blood and the other is venous blood. You can choose different blood glucose testing methods according to the purpose, time and place of testing: 1. Fingertip blood: Because fingertip blood is convenient and easy to operate, it is mostly used for daily life or clinical blood glucose testing. Patients who are determined to be diabetic or have reduced glucose tolerance can use fingertip blood glucose value as a reference for testing. Usually, fasting blood glucose, pre-meal blood glucose and post-meal blood glucose are used as the standard for testing. Fasting blood glucose is the state of fasting and water fasting for more than 8 hours, pre-meal blood glucose is the blood glucose before eating, and post-meal blood glucose is the blood glucose 2 hours after counting from the first bite. If people with no history of the disease find abnormal blood glucose by measuring fingertip blood, although it cannot be used as a diagnostic standard, they should go to the hospital for glucose tolerance test in time; 2. Venous blood: you need to go to the hospital for venous blood sampling, compared with fingertip blood, venous blood is more accurate and is one of the means to diagnose whether you have diabetes, glucose tolerance test is to use venous blood for judgment, compared with fingers, there is no venous blood and The glucose tolerance test is performed using venous blood, and the results are more accurate because there is no influence of venous blood and tissue fluid. Fasting blood glucose is the blood glucose after 8 hours of fasting, and postprandial blood glucose is mostly the blood glucose 2 hours after meal. The fasting blood glucose of normal people is 3.9-6.1mmol/L, and the blood glucose of 2 hours after meal does not exceed 7.8mmol/L. If the fasting blood glucose reaches 7.0mmol/L or the postprandial blood glucose reaches 11.1mmol/L, diabetes can be diagnosed. If pre-meal blood glucose is 6.1-7.0mmol/L, impaired fasting blood glucose is diagnosed. If the postprandial blood glucose is 7.8-11.1mmol/L, the diagnosis is abnormal glucose tolerance. There are many reasons that can affect blood glucose values, including exercise, diet and even emotional excitement, so it is important to avoid these aspects when measuring blood glucose. Before measuring blood glucose, patients usually do not need to stop medication and fasting if there is no special requirement. Normal measurement is necessary to know the blood glucose level in normal condition, which is convenient for treatment and regulation.