GlucoseClinical significanceThe primary aim of laboratory diagnosis is to assess the carbohydrate metabolism impairment in diabetes mellitus, including the following:1) determination of glucose concentration in fasting blood and demonstration of postprandial glycosuria; and 2) assessment of glucose tolerance. Fasting glucose concentration.
Normal values of fasting blood glucose do not exclude an impairment, because many patients with diabetes mellitus may have fasting blood glucose within the reference range. Therefore, the blood glucose concentration is determined 2 hours after the last meal. In healthy individuals, the concentration of blood glucose at 2 hours postprandially will be within the reference range. If the glucose value is normal at 2 hours postprandially, a carbohydrate metabolism impairment can most probably be excluded. The findings falling within the borderline or pathologic area should be repeated on several occasions before making a definite diagnosis. The World Health Organization (WHO) criteria for the diagnosis of carbohydrate metabolism disturbances are presented in Table. WHO criteria for the diagnosis of diabetes mellitus
Diseases associated with hyperglycemia Diabetes mellitus Diabetes mellitus develops due to complete or relative insulin deficiency. It rarely occurs after an irreversible lesion of the endocrine part of the pancreas or due to enhanced action of insulin antagonist hormones. It usually develops as a primary disease. According to WHO classification, there are two types of the disease. Main types and characteristics of diabetes mellitus
Insulin deficiency leads to impairment in the metabolism of carbohydrates as well as of lipids and protein. The disease severity depends on the grade of metabolic disturbance. Fasting hyperglycemia occurs in case of major insulin deficiency, and glycosuria develops when glucose concentration exceeds renal threshold (>10 mmol/L). 1) Physiologic variations in serum glucose concentration An increase in serum/plasma glucose between 9 and 10 a.m., 2 and 3 p.m. and after 6 p.m. probably is a transient response of the body to the respective meals. A) Increased fasting glucose concentration consequential to the increased adrenaline level in the circulation in: • hard physical activity, • strong emotions, e.g., fear. B) Decreased fasting glucose concentration: • normal pregnancy (mild hypoglycemia), • severe hypoglycemia occurs in normal neonates born to diabetic mothers. • within 2-4 hours postnatally, blood glucose falls to the lowest level, returning to the birth value in 3-5 days 2) Pathologic changes in serum glucose concentration
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