Fasting for too long causes blood sugar to rise? It doesn’t have to be diabetes!

In daily life, blood sugar testing has become an indispensable part of many people's lives. However, some people find that their blood sugar is high after fasting for a long time. In fact, this does not necessarily mean that they have diabetes, because this exists in women and is also affected by other psychological factors. An accurate judgment can be made by testing glycated hemoglobin, glycated serum protein, insulin and C-peptide.

1. If my fasting blood sugar level is elevated, does it necessarily mean I have diabetes?

Don't panic, it's not certain.

First of all, under normal circumstances, the fasting blood glucose concentration is relatively constant in the range of 3.89~6.11 mmol/L. This is the result of the dynamic balance of the source and destination of blood glucose under the regulation of multiple factors such as nerves, hormones, liver and kidneys. It is also the result of the coordinated metabolism of various tissues and organs such as liver, muscle, and adipose tissue. In addition, blood glucose concentration is also affected by various other physiological factors (such as diet, sleep, exercise, menstrual cycle, pregnancy, drugs, dawn phenomenon), as well as various pathological factors (such as craniocerebral injury, vomiting, diarrhea, high fever, anesthesia, infection, toxemia, pancreatitis), etc.

Secondly, there are many factors that affect blood sugar measurement by fingertip blood sampling at home, and the results can only be used as a reference. Even the results measured in hospitals and laboratories will vary. This is because there are many methods for measuring blood sugar, such as: hexokinase method, glucose oxidase method, glucose dehydrogenase method and many other methods. Each hospital's laboratory uses different methods, and the results obtained will be different.

Moreover, if blood sugar is measured high at one time, it is likely accidental, such as consuming too much sweets in the diet. It is recommended to perform two consecutive measurements, or to measure other diabetes-related test items.

Diabetes is a group of metabolic diseases caused by insufficient insulin secretion or (and) low insulin action. Typical symptoms are increased appetite, increased drinking, polyuria and weight loss, sometimes accompanied by decreased vision and susceptibility to secondary infection. Adolescent patients may experience growth retardation.

2. Test the following items related to diabetes:

1. 2-hour postprandial blood glucose, a simplified glucose tolerance test, the reference interval is 2-hour postprandial blood glucose <7.8 mmol/L;

2. Glycated hemoglobin, the reference interval is <6.5%, which reflects the average blood sugar concentration in the past 3 months. It does not require fasting or blood sampling at a specific time, and is not easily affected by acute blood sugar fluctuations. The test results can be used as a guide for blood sugar treatment;

3. Glycated serum protein and glycated albumin. The reference range is glycated serum protein (1.65~2.15) mmol/L, and glycated albumin is 10.8%~17.1%, which can reflect the blood sugar control situation 2-3 weeks ago;

4. For insulin and C-peptide, the reference range is fasting insulin (ECLIA method): 17.8~173.0 pmol/L, C-peptide (ECLIA method): 250.0~600.0 pmol/L, which can be used to evaluate patients with fasting hypoglycemia.

Finally, if other diabetes-related items measured in the hospital show no obvious abnormalities, you should consider whether the secondary increase in blood sugar is caused by other metabolic diseases. You can go to other departments such as endocrinology for corresponding tests to rule it out.