blood glucose

Serum glucose is determined by an o-toluidine method, a glucose oxidase method, a glycosyl kinase method, a glucose dehydrogenase method, and a dry chemical method. Among them, the glycokinase method is an internationally recommended reference method, but the reagents are relatively expensive. The glucose oxidase method recommended in China is widely used at home and abroad. At present, some units still use the o-toluidine method. Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: After 8 pm on the day before the medical examination, you should fast, so as not to affect the detection of indicators such as blood glucose in the second sky. Normal value 1-o-toluidine method (O-TB): 3.89 to 6.11 mmol/L. 2 glucose oxidase method (GOD): 3.89 ~ 6.11 mmol / L. 3 spectrophotometry (AAS): 3.88 to 5.8 mmol/L. 4 automatic biochemical analyzer: 3.89 ~ 6.11mmol / L. (2) 2 h <6.7 mmol/L (<120 mg/dl) after eating. Clinical significance (1) rise 1 insulin secretion is insufficient for true diabetes. 2 glucocorticoids increase acromegaly, hyperthyroidism, Cushing's syndrome, giant disease. 3 adrenaline too pheochromocytoma. 4 liver intake reduces cirrhosis, severe hepatitis, hemochromatosis. 5 intracranial pressure increased brain trauma, brain tumor, cerebral hemorrhage, severe suppurative meningitis. 6 Vitamin B1 lacks Wernicke encephalopathy (cerebral hemorrhagic polio). 7 pancreatic cancer, acute and chronic pancreatitis, islet alpha cell tumor and the like. 8 stress state burns, shock, emotional trauma, anesthesia, etc. 9 drugs and chemical poisoning poisoning caffeine, theophylline, ACTH, carbon monoxide and heavy metal poisoning. (2) lower 1 excessive insulin secretion: islet β-cell tumor, extra-pancreatic tumor (adrenal cancer, gastric cancer, fibrosarcoma), dumping syndrome, early diabetes, functional hypoglycemia, nourishing hypoglycemia, glucagon deficiency Symptoms, etc. 2 anti-insulin endocrine deficiency: anterior pituitary hypofunction, Addison's disease, islet alpha dysfunction, hypothyroidism (small stagnation, mucinous edema). 3 Insufficient supply of liver glucose: primary liver cancer, late stage cirrhosis, severe hepatitis, severe fatty liver, glycogen storage disease (VonGierKe disease), galactosemia, long-term malnutrition, etc. 4 other subarachnoid hemorrhage, post-encephalitis syndrome, lychee disease, leucine allergy, inadequate food intake, exercise, hunger, drugs (taking insulin or hypoglycemic agents). Precautions Obey the doctor's arrangements before the examination. Inspection process (1) Determination of glucose o-toluidine (O ~ TB) method: 1 In addition to glucose, other sugars can also produce colored compounds during the reaction. Their absorbance ratios are: glucose = 1.00, fructose = 0.06, mannose = 0.96, galactose = 1.42, sucrose = 0.16, maltose = 0.09, lactose =0.39, xylose = 0.12. However, in these sugars, glucose, fructose and galactose are present in normal human serum, while the latter is in a small amount in normal human blood and does not affect the actual measurement results. 2 The color development intensity of the determination solution is related to the reaction conditions. The batch number of o-toluidine, the new and old o-toluidine reagent (if the reagent is too long after preparation, the color becomes light), and the heating temperature and heating time will affect the color development intensity. . Therefore, the heating time and temperature of the measuring tube, the standard tube and the blank tube must be exactly the same. The number of tubes to be measured per batch should not be too large in order to better control the reaction conditions. Some batches of glacial acetic acid produce a brown reaction that affects the results. 3 The final reaction solution occasionally produces turbidity, the most common cause is hyperlipidemia. At this time, 1.5 ml of isopropanol can be added to 3 ml of the color developing solution, and the mixture is thoroughly mixed. The lipid is dissolved to eliminate the turbidity, and the measured absorbance is multiplied by 1.5. When dextran is injected, turbidity is caused by the insoluble of dextran in the o-toluidine reagent. Turbidity can also occur when the cold water bath is too cold. 4 mild hemolysis does not affect the measurement, but 1g / L hemoglobin can falsely increase the glucose measurement results. The results of the 5-o-toluidine method were basically the same as those of the glucose oxidase method and the glycosylation method, but the results of the o-toluidine method were slightly higher in uremic patients. 6 o-toluidine reagent is toxic and carcinogenic, should be avoided by skin contact or direct inhalation. (2) Glucose oxidase (GOD) method: 1 Glucose oxidase is highly specific for β-D glucose. About 36% of glucose in solution is α-type and 64% is β-type. Complete oxidation of glucose requires a cyclonic reaction from alpha to beta. Some domestic glucose oxidase kits contain glucose mutase, which can accelerate this reaction, but the incubation time can be extended in the end point method to achieve the spontaneous spinning process. The newly prepared glucose standard solution is mainly of the α type, so it must be placed for more than 2 hours (preferably overnight), and can be applied after the rotation is balanced. 2 The specificity of the glucose oxidase assay is high, and the substances that can interfere with the determination result are few. The concentration of hemoglobin in the hemolyzed specimen is 10g/L, and the concentration of bilirubin in the xanthine specimen is 342μmol/L. The concentration of sodium fluoride is 2g/L, the concentration of urea is 46.7mmol/L (280mg/dl), the concentration of uric acid is 2.95mmol/L, the concentration of cysteine ​​is 50mg/dl, and the concentration of triglyceride is 500mg/dl. There was no effect on the measurement results, and vitamin C, glutathione, and 10 mg/dl levodopa may cause a negative bias in the measurement results. 3 If the blood sugar is measured, the sample is preferably potassium oxalate-sodium fluoride as an anticoagulant. Take 6 g of potassium oxalate, 4 g of sodium fluoride, dissolve it in water to 100 ml, draw 0.1 ml into a glass test tube, and dry it at 80 ° C or lower to make 2 to 3 ml of blood not coagulate for 3 to 4 hours and inhibit sugar decomposition. 4 Methodological evaluation: The linear range of GOD method is at least 19mmol/L, the recovery is 94%-105%, the coefficient of variation is 0.7%-2.0% within the batch, 2% between batches, and 2%-3% during the day. . Accuracy and precision can meet clinical needs, easy to operate, and suitable for routine testing. Not suitable for the crowd 1. Patients who have taken contraceptives, thyroid hormones, steroid hormones, etc., may affect the results of the examination and prohibit patients who have recently taken the drug history. 2, special diseases: patients with hematopoietic function to reduce disease, such as leukemia, various anemia, myelodysplastic syndrome, etc., unless the examination is essential, try to draw less blood. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye. 3, dizzy or fainting: in the blood draw, due to emotional overstress, fear, reflex caused by vagus nerve excitement, blood pressure decreased, etc. caused by insufficient blood supply to the brain caused by fainting or dizziness. 4. Risk of infection: If you use an unclean needle, you may be at risk of infection.