Blood sugar test: rules for delivery, norms, decoding
The content of the article:
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Preparation for analysis and rules for blood sampling
Glucose tolerance test
- Blood sugar test rate
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Blood sugar test results
- Hyperglycemia
- Hypoglycemia
A blood sugar test is a common household name that is used to refer to the laboratory determination of glucose concentration in blood.
Glucose is the main energy substrate that supports the body's metabolic processes. The content of glucose in the blood is regulated by the hormone insulin, which ensures its penetration into cells. Excess glucose is deposited in the body as glycogen, which is deposited in the muscles and liver.
A blood sugar test is done during routine medical examinations A blood sugar test is done during routine medical examinations
A blood test for sugar, thus, allows you to get an idea of the most important - carbohydrate metabolism in the body. This study belongs to the main methods of diagnosing diabetes mellitus. With its regular passage, the biochemical changes inherent in diabetes mellitus can be detected several years before a clinical diagnosis is established.
A blood sugar test is included in the plan of all children's preventive examinations, allowing timely detection of type 1 diabetes mellitus. Annual determination of the concentration of glucose in the blood is recommended for all persons over 45 years of age in order to timely detect type 2 diabetes.
Preparation for analysis and rules for blood sampling
Before conducting the analysis, you can consult with a doctor who will explain how sugar is indicated in the decoding of the analysis, how to donate blood correctly to obtain reliable results, and answer questions that have arisen in connection with the study.
The indication for determining the level of glucose in the blood is a suspicion of the following pathologies:
- diabetes mellitus type 1 or 2;
- liver disease;
- pathology of the organs of the endocrine system - the adrenal glands, thyroid gland or pituitary gland.
In addition, the analysis for sugar is shown when determining the causes of obesity, impaired glucose tolerance. For prophylactic purposes, it is carried out in pregnant women, as well as during routine medical examinations.
Before the study, it is advisable to stop taking medications that can affect the level of glucose in the blood, but you should first check with your doctor if this is necessary. Before donating blood, you must avoid physical and mental stress.
To determine the glucose level, blood is taken in the morning on an empty stomach (8-12 hours after the last meal). You can drink water before donating blood. Blood sampling is usually done before 11:00. Whether it is possible to pass tests at another time should be clarified in a specific laboratory. Blood for analysis is usually taken from a finger (capillary blood), but it is also possible to take blood from a vein, in some cases this method is preferable.
If the test results show an increase in glucose levels, an additional glucose tolerance test, or glucose tolerance test, is performed, which diagnoses prediabetes and diabetes.
Glucose tolerance test
The study consists of determining the blood sugar level before and after the glucose load. The test can be oral or intravenous. After taking blood on an empty stomach, the patient takes orally, or he is injected with an intravenous solution of glucose. Next, the blood glucose level is measured every half hour for two hours.
For three days before the glucose tolerance test, the patient should follow a diet with the usual carbohydrate content, as well as adhere to normal physical activity and observe an adequate drinking regime. The day before blood sampling, alcoholic beverages should not be consumed, and medical procedures should not be carried out. On the day of the study, it is necessary to stop smoking and take the following drugs: glucocorticoids, contraceptives, adrenaline, caffeine, psychotropic drugs and antidepressants, thiazide diuretics.
The indications for a glucose tolerance test are:
- overweight;
- arterial hypertension;
- atherosclerosis;
- gout;
- chronic liver disease;
- furunculosis;
- periodontal disease;
- metabolic syndrome;
- polycystic ovary syndrome;
- neuropathy of unknown etiology;
- habitual miscarriage; and etc.
The test is indicated with prolonged use of glucocorticosteroids, estrogen preparations, diuretics, as well as with a family predisposition to impaired carbohydrate metabolism.
The test is contraindicated in the presence of severe diseases, after surgery, childbirth, in diseases of the digestive tract with malabsorption, as well as during menstrual bleeding.
With endocrine diseases, hypokalemia, impaired liver function, test results may be false positive.
When a result is obtained that goes beyond the normal values of blood glucose, a general urine test is prescribed, the determination of glycosylated hemoglobin in the blood (usually written in Latin letters - HbA1C), C-peptide and other additional studies.
Blood sugar test rate
The rate of glucose in the blood is the same for women and men. Normal values of the indicator depending on age are presented in the table. It should be borne in mind that in different laboratories, depending on the diagnostic methods used, the reference values and units of measurement may differ.
Norms of concentration of glucose in venous blood
Age Reference values, mmol / l Up to 1 year 2.8-4.44 1-5 years 3.3–5 6-18 years old 3.3-5.5 Over 18 years old 4-6 When conducting a glucose tolerance test, the concentration of glucose in the blood two hours after glucose load should not exceed 7.8 mmol / L. Indicators from 7.8 to 11.1 mmol / l indicate impaired glucose tolerance. If 11.1 mmol / l is exceeded, diabetes mellitus is diagnosed.
A false negative result can be due to significant physical activity on the eve of the study. A false positive result can be caused by bed rest during glucose load, disinfectants entering the capillary blood, and other errors.
Blood sugar test results
Hyperglycemia
An increase in blood glucose concentration (hyperglycemia) is observed in type 1 or type 2 diabetes mellitus in children and adults, Itsenko-Cushing's syndrome, thyrotoxicosis, pheochromocytoma, somatostatinoma, pancreatitis, hemochromatosis, pancreatic neoplasms, cystic fibrosis, chronic myocardial infarction, liver disease or kidney, the presence of antibodies to insulin receptors, taking certain medications (caffeine, calcitonin, diuretics, glucocorticosteroids, estrogen, adrenaline, oral contraceptives, morphine).
Physiological increase in glucose levels occurs with a strong emotional shock, moderate physical exertion, stressful situations, smoking.
Blood glucose levels rise during pregnancy, as the sensitivity of body tissues to the action of insulin decreases. A persistent increase in blood sugar in pregnant women may indicate gestational diabetes mellitus, or pregnancy diabetes. Gestational diabetes is not a harmless condition, it increases the risk of developing acute pyelonephritis, preeclampsia, spontaneous abortion, and birth complications. After childbirth, the glucose content usually returns to normal, in rare cases, gestational diabetes mellitus turns into true diabetes.
Diabetes in pregnancy increases the risk of miscarriage and birth complications Diabetes in pregnancy increases the risk of miscarriage and birth complications
Hypoglycemia
A decrease in the concentration of glucose in the blood (hypoglycemia) is characteristic of pathologies of the pancreas, liver cirrhosis, hepatitis, hemochromatosis, hypothyroidism, Addison's disease, adrenal or stomach neoplasms, hypopituitarism, ketotic hypoglycemia. This condition is observed in premature infants, with impaired intestinal motility, prolonged fasting, alcohol abuse, impaired fructose tolerance, prolonged fever, excessive physical exertion. In addition, blood glucose levels decrease when taking antihistamines, salicylates, insulin, oral hypoglycemic drugs, amphetamine, marijuana.
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Anna Aksenova Anna Aksenova Medical journalist About the author
Education: 2004-2007 "First Kiev Medical College" specialty "Laboratory Diagnostics".
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