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(A) urine glucose test results should pay attention to the following situations. Urine test results for diagnostic purposes only, and diagnosed diabetes depends on blood glucose measurement.
1. If there is a small amount or trace of diabetes, and occasionally appear after meal should be carried out blood glucose and glucose tolerance test, and noted that the spotted solution of copper sulfate was reduced to copper oxide and the like to react, a lot of drugs , Such as morphine, salicylates, chloral hydrate, aspirin, para-aminobenzoic acid, a large number of citric acid, uric acid, and many other carbohydrates can also be raw copper sulfate and false-positive results. It is now widely used glucose oxidase made of urine test strips, to avoid false-positive results.
2. clinically diabetic signs or suspects and urine negative repeatedly, should pay attention to the determination of fasting and 2 hours after a meal blood sugar, so that except for elevated renal glucose threshold.
(B) of the blood glucose determination of blood glucose methods commonly used in three: venous plasma glucose (VPG), capillary blood glucose (CBG) and intravenous whole blood glucose (VBG). Of the two most commonly used before. The results obtained by different methods are slightly different. The results of the VPG method are 10% higher than those of CBG and about 15% higher than that of VBG. In the analysis of blood glucose report should pay attention to the exclusion of other cases caused by increased glucose concentration, such as injection of sugar, a variety of endocrine disorders, brain lesions and stress conditions, which will be described later. Patients with mild or early, especially type Ⅱ disease may be normal fasting blood glucose, can not be easily excluded, must be 2 hours after a meal blood glucose or glucose tolerance test.
(C) glucose tolerance test for patients with normal or slightly higher fasting blood glucose and occasionally diabetic, or suspected patients with diabetes (such as a positive family history, or repeated miscarriage, premature birth, stillbirth, giant baby, dystocia, abortion After the maternal, or repeated sore boil, etc.), to be glucose tolerance test. But the fasting blood glucose significantly increased the diagnosis of dominant cases have been identified, a lot of glucose can burden, should be exempted.
Diagnosis of diabetic fashion to be excluded except for a variety of factors affecting glucose tolerance, including anterior pituitary, adrenal cortex, hyperthyroidism and other endocrine diseases, obesity, liver disease, a variety of drugs (such as thiazide diuretics, female contraceptives, glucocorticoids , Phenytoin, chlorobenzothiadiazine, etc.), stress conditions (such as fever, infection, acute myocardial infarction, surgery, etc.), loss of potassium and so on.
2. 2h after meals blood glucose measurement Equivalent to 100g glucose carbohydrate foods such as steamed 2 2 or rice 2h after the determination of blood glucose, such as more than 140mg / dl were reduced tolerance, ≥ 200mg / dl for diabetes.
Because of low sugar diet or hunger state can reduce impaired glucose tolerance, so should pay attention to adjust the diet 3d pre-test sugar intake of not less than 250g / d, in order to obtain reliable results.
For some patients to assess their β-cell function or glycemic control status, the following determination can be made:
1. Fasting plasma insulin measured in our hospital by radioimmunoassay fasting plasma insulin normal range of 5 ~ 20μu / ml, type I patients are often below 5μu / ml, sometimes as low as undetectable. Type II plasma insulin levels in patients with normal, a few also have low, obese patients often higher than normal, increased significantly hyperinsulinemia, suggesting that insulin resistance. The latter is a component of the metabolic syndrome can be considered as one of the risk factors for coronary heart disease, which has drawn much attention in recent years. Insulin and insulin original immune cross, and therefore can be measured for the general radio immunoassay, and cardiovascular adverse effects, proinsulin may be more than insulin. The study has been the determination of proinsulin used in clinical.
2. Insulin release test During oral glucose tolerance test, plasma insulin concentration can be measured simultaneously to reflect the islet β-cell reserve function. In addition to the low fasting level of type I patients, the level of insulin remained low after the stimulation of sugar, showing a low flat curve, especially the simultaneous calculation of the ratio of glucose to insulin (IRI) / G, suggesting that insulin secretion Low (normal 25μu / mg). Ⅱ type of patients fasting level may be normal or high, delayed release after stimulation. Glucose stimulation, such as insulin did not rise or flat water, suggesting that β-cell dysfunction.
3.C-peptide determination of insulin release from pancreatic β-cells by the liver and kidneys by insulin and other energy-extinction, the peripheral blood of each cycle will be 80% destroyed, and its half-life of only 4.8 minutes, so the blood concentration of only Represents a very small part of its total secretion. C peptide and insulin from the proinsulin split from the same molecular peptides, not by the liver enzyme excretion, only excretion by the role of the kidneys, and its half-life of 10 to 11 minutes, so the blood concentration can be more Good reflection of pancreatic β-cell reserve function. Determination of C-peptide is not affected by insulin antibodies interfere with the determination of insulin-free cross-immune reaction, and is not affected by insulin injection, it has been used in recent years measured C-peptide blood concentration or 24-hour urinary excretion to reflect the beta cell secretion Features.
(1) Serum C-peptide concentration determination: Normal human serum C-peptide was 1.0 ± 0.23 mg / dl when fasting was measured by radioimmunoassay. The concentration was 3.1 ng / ml when the peak value of oral glucose was seen for 60 minutes. Serum C-peptide increased from 1.3 ± 0.3 ng / ml to 4.4 ± 0.8 ng / ml after 60 minutes in normal subjects and only 2.3 ng / ml in type 2 diabetes after 2 hours. The other 5 cases of type Ⅰ patients who had been treated with insulin for more than 5 years, C peptide levels are low, both fasting and after stimulation failed to measure.
⑵ 24-hour urine C peptide determination: normal 24-hour urine C peptide 36 ± 4μg, type I only 1.1 ± 0.5μg, type Ⅱ patients was 24 ± 7μg, C peptide daily release equivalent to about the secretion of insulin 5% of the amount of insulin secretion and only 0.1%.
The above-mentioned C-peptide assay can identify β-cell function in type I patients with insulin treatment, which is not only used for scientific research but also clinically used at present.
4.HbA1c determination of fasting blood glucose and blood glucose fluctuations may reflect the recent 2 to 3 months in the blood glucose, normal HbA1c6%, HbA1 8%, often higher than normal in patients with diabetes.
Fructosamine determination of serum normal fructosamine 2.13 ± 0.24mmol / L (plasma low 0.3mmol / L), reflecting the last 1 to 4 weeks of blood glucose, parallel with HbA1c, regardless of type I diabetes, type Ⅱ Are higher, especially in type Ⅰ as high.
In short, the diagnosis of diabetes can root history, clinical manifestations, supplemented by the above urine sugar, blood glucose and OGTT determined. In addition, the need to identify whether there are various complications and complications, and to assess their severity, type, stage of development and major organ status, etc., is very important for the treatment and prognosis of the disease.
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