Auntie Wang, 58 years old, has been suffering from type 2 diabetes for 10 years, and started to inject insulin twice a day last year. I monitor my blood glucose every day and adjust my insulin dosage according to my blood glucose, but I can’t adjust it well, my blood glucose is either high or low, why is that?” I checked her blood glucose record in detail and asked her about the process of insulin adjustment, and I understood what was wrong with her. It turned out that she was increasing the amount of insulin injected before breakfast when she saw that her fasting blood sugar was high, and increasing the amount of insulin before dinner when she saw that her blood sugar was high after Chinese food, and as a result, she often felt hungry or had a hypoglycemic reaction at night, and was hyperglycemic again on a fasting stomach the next day after eating. If she knew the meaning of blood glucose monitoring and how to monitor it, the above situation would not have happened. A good blood glucose monitoring can help doctors and patients themselves to control blood glucose better, and can also make themselves become their own diabetes doctor. 1. Test whether your blood glucose meter is accurate – compare with biochemical test While drawing blood to test fasting blood glucose, use your own blood glucose meter to test blood glucose at the same time, the difference should not exceed 20%, if it exceeds 20%, you should look for the reason. Whether the test paper is expired, whether the test paper code is consistent with the code of blood glucose meter, whether the operation method is correct, whether you have anemia, edema, dehydration, etc. 2. Frequency and time of testing – according to the condition (1) If the blood sugar control is good and stable and the environmental factors remain unchanged, monitor the blood sugar once a week on fasting and once 2 hours after breakfast. Patients with poor blood glucose control or those in critical condition should be monitored 4~7 times a day until the condition is stable and blood glucose is controlled. (2) Monitor blood glucose before and after exercise to prevent hypoglycemia after exercise. If blood glucose is <5.6mmol/l, eat a small amount of food before exercise. (3) The frequency of monitoring should be increased when changing medication and dosage. For those who use insulin therapy, blood glucose should be measured at least 5 times a day at the beginning of treatment, fasting, 2 hours after 3 meals and before bedtime; self-monitoring blood glucose 2~4 times a day after reaching the treatment goal; monitoring blood glucose 2~4 times a week for patients who use oral medication and lifestyle intervention. (4) If there are stress factors and dietary changes, the monitoring frequency will be increased. For example, the occurrence of some acute diseases such as cold and diarrhea, and the change of diet quantity and frequency. 3. How to evaluate the monitored blood glucose - comprehensive analysis (1) Fasting blood glucose: It reflects the level of basal insulin secretion in human body. It can help to understand the control of blood glucose at night and help to decide the adjustment of treatment or bedtime meal addition. If the above-mentioned patient has high fasting blood glucose, after excluding nocturnal hypoglycemia and dawn phenomenon, it can be considered as the cause of insufficient insulin dose before dinner, and the insulin dose can be increased before dinner. (2) Preprandial blood glucose: It is helpful to detect hypoglycemia and find out whether the cause is diet or drug dose. (3) Two-hour postprandial blood glucose: It reflects the level of additional insulin secretion by human body after meal, and helps to adjust diet plan and drug type. If the above-mentioned patients have elevated blood glucose after breakfast and lunch, we can consider that the insulin dose before breakfast is insufficient under the exclusion of the factors of eating more meals, and we can increase the insulin dose before breakfast instead of adding the insulin dose before dinner. (4) Bedtime glucose measurement to prevent nighttime hypoglycemia and ensure safety at night. To determine the cause of morning hyperglycemia in order to adjust the drug dose 4. Myths of monitoring blood glucose (1) Stopping the drug when monitoring blood glucose: We monitor blood glucose for two purposes, one is to fully understand the status of blood glucose before the drug is used and reasonably use the drug according to blood glucose; the second is to understand the effect after the drug is used in order to further adjust the drug dose, so when the patient uses the drug, he should monitor the blood glucose after the drug is used should not stop monitoring the drug. (2) Measurement of fasting blood sugar after taking hypoglycemic drugs before breakfast: We monitor fasting blood sugar to observe the effect of medication of the previous day, and if hypoglycemic drugs are taken on an empty stomach, the blood sugar value will be affected and the effect of medication of the previous day will not be judged. Therefore, it is better for patients not to take medicine before measuring blood sugar on an empty stomach. (3) Inconsistency between finger blood glucose and venous blood glucose: theoretically, they are consistent, and even the difference is very small. Venous blood glucose is measured with venous plasma, which is after separating off red blood cells. Finger blood is capillary whole blood, including plasma and red blood cells, and red blood cells contain less glucose than plasma, so the blood glucose value of finger blood when fasting should be lower than the plasma blood glucose value of venous blood, and because there is often exudation of tissue fluid when taking finger blood, the blood glucose of finger blood is more likely to be lower than the plasma blood glucose of venous blood. However, after eating, the glucose absorbed by the body first goes to the arteries, and then returns to the veins after consuming part of the glucose through the peripheral metabolism of the capillaries, so the arterial blood glucose value is higher than the venous blood glucose value at this time. But this is exactly the opposite of the above-mentioned relationship between finger blood glucose and venous plasma glucose due to red blood cells and tissue fluid, so after eating, these two factors cancel each other out, making capillary whole blood glucose and venous plasma glucose about the same.