A blood test for sugar is an expression, albeit a generally accepted, but not quite true, incorrect. The expression “sugar in the blood” has historical roots: in the Middle Ages, doctors believed that the cause of increased thirst, frequent urination and pustular infections depends on how much sugar is in the blood of a person. Today, doctors know that there is no sugar in the blood: studies prove that all simple sugars are converted into glucose as a result of chemical reactions, and glucose plays one of the main roles in metabolism. And, speaking about the norms of blood sugar, they mean glucose concentration, a universal supplier of energy for all human organs and tissues.
“Blood sugar” or glycemia
Indications of glucose concentration in the blood (or blood sugar, as the non-specialists usually say) are called glycemia. Blood sugar exists only in the form of a monosaccharide, glucose, the level of its concentration and its fluctuations largely determine human well-being and health.
When assessing the indicator, they are guided by the blood sugar standards: hypoglycemia is diagnosed with a reduced amount of glucose, and hyperglycemia with an increased one. Hypoglycemia, regardless of the cause of the condition (chronic or acute illness, physical or emotional overstrain, failure to eat or low-carb diet) leads to poor health, because glucose is the “fuel material” primarily for the central nervous system, and also for virtually all organs and tissues. A drop in blood sugar levels may be accompanied by irritability, decreased stamina, impairment or loss of consciousness, until the onset of coma.
Temporary hypoglycemia is possible due to the above reasons. If the factors causing an increased glucose uptake or inadequate supply to the body last long enough, an adaptive tissue response is formed, against which a short-term increase in blood glucose can be recorded. Severe, prolonged hypoglycemia develops most often due to malnutrition with an abundance of sweets, simple carbohydrates in food. The pancreas in response to the intake of excess sugars begins to increase insulin production, which leads to an excessive accumulation of glucose in the tissues.
Other causes of hypoglycemia are disorders of the insulin-producing function of the pancreas, diseases of this organ, as well as kidneys, adrenal glands, and hypothalamus.
The first symptoms of hypoglycemia:
- sudden weakness;
- increased sweating;
- tremor, trembling in limbs and / or in the whole body;
- heart palpitations;
- irritability, irritability, agitation;
- strong feeling of hunger;
- disturbances of consciousness, dizziness, fainting.
In the presence of hypoglycemia, it is recommended that patients always carry with them food or liquid that supplies glucose in a rapidly digestible form: sugar, candy, and an aqueous solution of glucose. Important is the diet, the consumption of complex, slow carbohydrates, avoidance of increased physical and psycho-emotional stress, stress, adherence to the day, a good rest.
Hyperglycemia or excess of the level of sugar in the blood may be due to increased loads, a temporary condition. If a high concentration of glucose in the blood plasma is determined for a long time and repeatedly, then this most often indicates diseases of the endocrine system, in which the rate of glucose excretion exceeds the rate of absorption by its tissues.
A mild degree of physiological hyperglycemia does not cause significant damage to organs and tissues. Prolonged pathological hyperglycemia leads to severe metabolic disturbances, reduced immunity, blood supply, damage to organs and systems, and death.
Hyperglycemia as a symptom is characteristic of diseases such as diabetes mellitus, diseases associated with hyperfunction of the thyroid gland, impaired functioning of the hypothalamus, the brain area responsible for the activity of the endocrine glands, as well as for some dysfunctions and diseases of the pituitary and liver, in particular infectious hepatitis.
Symptoms of hyperglycemia include:
- strong, unquenchable thirst;
- increased urinary frequency;
- feeling of dry mouth;
- high fatigue, drowsiness;
- unexplained weight loss;
- visual impairment (vagueness, “fog before the eyes”);
- disturbances of emotional balance: irritability, irascibility, sensitivity;
- increased respiratory rate, increased inspiratory depth;
- the smell of acetone on the exhale;
- susceptibility to infectious diseases, especially bacterial, fungal, prolonged healing of superficial wounds of the epithelium;
- imaginary tactile sensations, most often in the lower limbs (tingling, goosebumps, running insects, etc.).
What is the rate of blood sugar?
A blood test allows you to determine the rate of sugar in the blood with a high frequency. Indicators of blood sugar, or glucose concentration, differ depending on the person’s age, meal time, and the characteristics of the blood itself with different methods of taking biological material: the rate of sugar in the blood from an empty vein differs from the rate of blood from a finger or after taking food.
In an adult, the blood sugar level is normally 3.2–5.5 mmol / l, regardless of gender characteristics (they do not differ in women and men). The indicator within this interval when assessing fasting blood sugar (capillary blood sampling from a finger) is considered normal. When assessing the level of glucose concentration in the analysis of sugar from a vein, the upper index increases to 6.1-6.2 mmol / l.
The results of tests in which blood sugar exceeds 7.0 mmol / l are considered a sign of pre-diabetes. Pre-diabetes is a condition characterized by impaired absorption of monosaccharides: on an empty stomach, the body is able to regulate the concentration of glucose, and after ingestion of carbohydrate food the amount of insulin produced does not meet the needs.
How do you know if elevated blood sugar is evidence of prediabetes? In such cases, to confirm or differentiate the diagnosis, an additional blood test for sugar is performed: blood sugar or glycemic index is determined twice after the patient has taken an aqueous solution of glucose. The interval between taking and the first test is 1 hour, between taking and the second checking of blood sugar is 2 hours.
Normally, blood sugar, or glucose, is absorbed by the tissues, and its indices decrease in accordance with the time interval after administration of the glucose solution. In identifying concentrations from 7.7 to 11 mmol / l in the second analysis diagnosed impaired tissue tolerance to glucose. In this condition, the symptoms and signs of diabetes may be absent, but will develop in the absence of the necessary therapy.
Blood sugar: age norms
The interval from 3.3 to 5.5 mmol / l is considered the norm for people aged 14 to 60 years. For other age periods are guided by the following data:
Age Level of blood glucose, mmol / l
From birth to 1 month 2.8-4.4
Till 14 years old 3.3-5.6
From 14 to 60 years 3.2-5.5
From 60 to 90 years 4.6-6.4
Over 90 years 4,2-6,7
Age intervals are the same for men and women. However, in women in the gestational period, the indicators can be slightly increased, the normal glucose concentration in women during pregnancy can vary from 4.6 to 6.7 mmol / l. When indicators are exceeded, gestational diabetes is diagnosed. Elevated blood sugar in women during gestation when the physiological norm is exceeded indicates endocrine disorders and requires appropriate therapy to preserve the health of the mother and child. The blood glucose test is on the list of studies that are required for the expectant mother.
Also, age-related increases in the normal level for women can vary depending on the time of menopause and the endocrine changes associated with it in the body. On average, after 50 years of age, preventive consultations with a specialist and tests for glucose concentration in the blood should be carried out at least once every 6 months, even in the absence of symptoms.
What are blood sugar levels for diabetes?
What are the test results for diabetes? If fasting blood sugar exceeds 7.0 mmol / l when capillary blood is taken, it is most often an indicator of diabetes. To confirm the diagnosis, an analysis with carbohydrate loading is carried out (test for glucose tolerance): an increase in the glycemic index after taking glucose solution to 11.1 mmol / l and above. However, the glycemic index is not the only indicator by which diabetes diagnosis is differentiated.
Indicator For diabetics in healthy people
Sugar in the morning on an empty stomach, mmol / l 5,0-7,2 3,9-5,0
Sugar after 1 and 2 hours after a meal, mmol / l below 10.0, usually not higher than 5.5
Glycated hemoglobin HbA1C,% below 6.5-7 4.6-5.4
To clarify the causes of hyperglycemia conduct a series of studies, in particular, the analysis of glycated hemoglobin. This blood test reveals the proportion of red blood cells that have undergone changes due to an excess of glucose in the plasma. The irreversible reaction of hemoglobin in erythrocytes demonstrates the development and extent of the disease over the previous 3 months. Such a retrospective of changes reveals the time of occurrence of violations, the stage of development of the disease, the severity of negative effects on the body.
In a healthy person, the proportion of glycated hemoglobin in the blood does not exceed 6%, in a patient with diabetes in compensated form, it can be from 6.5 to 7%. Indicators of more than 8% in patients with a previously established diagnosis indicate the ineffectiveness of treatment of the disease or a violation of the diet and treatment regimen.
For patients with diabetes, the norm or the so-called stage of compensated diabetes is considered to be 5.0-7.2 mmol / l. It was revealed that the average fasting glucose levels in patients with such a diagnosis may differ depending on the season, increasing by winter and decreasing by summer, since the susceptibility of cells to insulin and the function of its production by the pancreas correlate with environmental conditions and depend not only from the physical and emotional state of a person, but also from climate change.
Rules for preparing blood glucose tests
Depending on the type of analysis, the preparation options for it vary. A fasting test, when taking venous or capillary blood, means a break between analysis and the last meal for at least 8 hours. At the same time it is necessary to refrain not only from food, but also from receiving any liquid. Unsweetened tea, pure water can affect the results of the analysis, reducing the concentration of glucose in the blood, and make the study ineffective.
Eating leads to insulin production in the pancreas and an increase in blood glucose levels. After 1 hour after eating, the concentration increases on average to 10 mmol / l, after 2 hours, the figures decrease to 8 mmol / l. The composition of the food also matters. After meals rich in carbohydrates, you must pause for up to 14 hours before analyzing on an empty stomach.
Indicators of glucose concentration in the classical analysis may vary under the influence of various factors. These include not only food and fluid intake, but also physical exertion, emotional distress, the presence of infectious diseases. The results of the analysis can be influenced by a walk from home to the clinic for half an hour, and a visit to the gym, active leisure activities a day before the analysis. In this case, the increased glucose level will decrease due to the load and the state of pre-diabetes will be difficult to detect. Indicators that do not correspond to the average level of glucose in the blood, which is characteristic of this person, are also distorted after insufficient night rest, night work shift, long trips, and stress.
Indications for an extraordinary study of sugar levels can be pruritus without localization in a particular place, increased thirst, frequent urination, feeling of dry mouth, as well as sudden unmotivated weight loss and an increase in the number of skin inflammatory diseases (abscesses, boils, abscesses) and fungal diseases (stomatitis, thrush, etc.). Diabetes is accompanied by a decrease in the body’s defenses, primarily skin immunity.
If there are symptoms, signs or suspicions of diabetes, it is recommended to conduct a study for the presence of glycated hemoglobin. At the moment, this biochemical indicator of blood is the most accurate in assessing the presence or absence of diabetic changes.
Analysis of the glycemic index should be taken as a preventive measure 1 time in 6-12 months, especially after reaching 40 years. Patients with overweight, pregnant women and people with a hereditary tendency to type 2 diabetes (with direct relatives with this diagnosis) are at increased risk.
If preventive purposes are recommended to healthy people for studies with a frequency of 1 time in half a year, then in the presence of diabetes mellitus the necessary frequency of glucose level assessment can reach 5 times a day. In type 1 diabetes, insulin-dependent, the concentration of glucose is necessary before each administration of insulin. With type 2 disease, a blood test is recommended after sleep, an hour after eating and before going to bed.
If a patient with diabetes has a change in the rhythm of life, there is a high physical or psycho-emotional stress, the analysis is recommended as often as possible.
If you need frequent self-monitoring of the glucose level, it is recommended to use portable blood glucose meters to assess the condition at home and prevent the development of diabetes complications.