Fasting blood glucose of 5.6 mmol/L in children indicates impaired fasting blood glucose in children, but does not meet the criteria for diabetes mellitus. Diabetes diagnosis criteria are fasting blood sugar greater than 7.0 mmol/L or glycosylated hemoglobin greater than 6.5%; with clinical symptoms of diabetes and blood sugar greater than or equal to 11.1 mmol/L 2 hours after oral glucose tolerance test; or with clinical symptoms of diabetes and blood sugar greater than 11.1 mmol/L at any time point. meeting any of the above conditions can clarify the diagnosis of diabetes. If the fasting blood glucose of children is greater than or equal to 5.6 mmol/L, it indicates impaired fasting blood glucose, and it is necessary to consider whether it is caused by obesity or family history of diabetes. If the child is obese, a glucose tolerance test should be conducted at the hospital to find out whether the child’s glucose tolerance is abnormal; if the child is not obese, a family history of diabetes should be clarified; if the child has a long-term increase in fasting blood glucose and does not meet the diagnostic criteria for diabetes, a genetic determination can be conducted to prevent diseases caused by genes.