What is the normal value of fasting blood sugar? 5 major experimental tests

Diabetic patients are generally divided into hyperglycemia and hypoglycemia. The elderly are at high risk of hyperglycemia. Hypoglycemia refers to blood sugar levels below 4.0mmol/l. Fasting blood sugar is a very important indicator that can guide patients on how to choose their diet. So how do you test the normal value of fasting blood sugar?

Normal fasting blood sugar

Fasting blood glucose (GLU) refers to the blood glucose value measured after fasting overnight (at least 8 to 10 hours without any food, except water) and before breakfast. It is the most commonly used test indicator for diabetes, reflecting the function of pancreatic β cells and generally representing the basal insulin secretion function.

The normal fasting blood sugar level is 3.89～6.1mmol/L. If it is greater than 6.1mmol/L and less than 7.0mmol/L, it means that the fasting blood sugar is damaged. If the fasting blood sugar is greater than or equal to 7.0mmol/L twice, diabetes is considered. It is recommended to recheck the fasting blood sugar and glucose tolerance test. If the random blood sugar is greater than or equal to 11.1 mmol/L, diabetes can be confirmed. If the blood sugar is lower than 2.8mmol/L, the corresponding clinical symptoms are called "hypoglycemia".

Normal blood sugar level is less than 7.8mmol/L 2 hours after meal. If blood sugar level is greater than or equal to 7.8mmol/L and less than 11.1mmol/L 2 hours after meal, it indicates impaired glucose tolerance. If blood sugar level is greater than or equal to 11.1mmol/L 2 hours after meal, it is considered diabetes (need to try again another day). (Excluding stress conditions, such as infection and trauma). At this time, formal treatment is required.

Experimental test

(1) Urine sugar measurement. The amount of glucose excreted in the urine of a normal person does not exceed 100 mg per day, and it cannot be detected by conventional urine sugar qualitative tests. If the amount of glucose excreted in the urine exceeds 100 mg per day, it is called diabetes.

(2) Blood sugar measurement. The glucose oxidase method is often used, and the o-toluidine method is also used. Normal fasting blood sugar is 3.9-6.1mmol/L. If the fasting blood sugar is ≥7.0mmol/L after two repeated measurements, diabetes can be diagnosed.

(3) Glucose tolerance test. Glucose tolerance test includes: ① oral glucose tolerance test (OGTT); ② intravenous glucose tolerance test (IGTT); ③ cortisone glucose tolerance test.

(4) Insulin measurement. Measurement standards: ① The normal value when fasting is 5-15 mU/L. Insulin-dependent people have a value lower than the normal lower limit or cannot be measured. Insulin-independent people have a value within the normal range or higher than normal people. ② Insulin release test: Insulin-dependent people have no peak and present a flat curve; Insulin-independent people have a lower peak than normal or a delayed peak.

(5) C-peptide measurement. ① The normal value in fasting blood is 1.0±0.23μg/L. In insulin-dependent patients, the level is reduced or undetectable, while in non-insulin-dependent patients, the level may be within the normal range or slightly lower. ② The C-peptide release test has the same curve as the insulin release test.