Which blood sugar test is more accurate: from a finger or from a vein?
In some situations, elevated plasma glucose levels are considered normal. Such situations are typical for injury. In the case of a strong emotional stress on a person, during the period of bearing a fetus, when a person is exposed to high physical activity. The phenomenon of hyperglycemia in such situations is observed for a short time.
The presence of pathological processes that increase the sugar level is evidenced by a long-term and sustained increase in plasma glucose concentration. The reason for such violations are failures in the functioning of the endocrine system, which regulates metabolic processes.
To determine the amount of glucose, laboratory tests are used, for this, blood is taken for sugar from a vein and from a finger.
Preparation for analysis and taking biomaterial
In order for a blood test for sugar from a vein and from a finger to be accurate, it is required to properly prepare for their delivery, and in the preparation process, follow certain rules.
Two days before the planned delivery of the biomaterial, it is required to abandon the use of drugs, tobacco smoking, the use of beverages containing alcohol and drugs. Immediately before taking the material for analysis, it is required to reduce the physical load on the body. Before taking a biomaterial, you should exclude the possibility of a strong emotional impact on the psyche.
12 hours before blood is taken from a vein or from a finger, food should be completely excluded.
Diet has a huge impact on glucose concentration. A prerequisite for obtaining reliable data is the refusal two days before they take blood for sugar from a vein or finger, from salty, spicy and fatty foods. Immediately before sampling biomaterial, it is undesirable to eat food containing dyes.
The biomaterial is taken on an empty stomach. Refusal to eat should be made at least 12 hours before the procedure. It is forbidden to use chewing gums and toothpaste before visiting the laboratory, this is due to the fact that the composition of these products very often contains carbohydrate, which, after contact with the gums, penetrates into the bloodstream.
Blood test from a vein and from a finger – what’s the difference?
The question of which blood sugar test is more accurate, from a finger or from a vein, can be answered in the affirmative. The data obtained by studying biomaterial obtained from the capillary network are less accurate for a number of reasons. The fact is that the quality can be influenced by a large number of factors, such as, for example, chilly hands, withdrawal symptoms and drug withdrawal.
Venous blood, devoid of the effect on its composition of tissue metabolites, informs about the average and more accurate glucose content for the whole organism.
The rate in the biomaterial taken from the venous bed should fluctuate in the range 4.6-6.1, and in the plasma obtained from the capillary network from 3.3 to 5.5 mmol / L.
A test for glucose concentration can be carried out in the laboratory of any medical institution, after receiving a referral for the study from the attending physician, which may be an endocrinologist, general practitioner or pediatrician.
The content is required to be checked regularly for people suffering from diseases such as diabetes, in addition to this, research is mandatory for women who are carrying a child.
Plasma glucose in children and pregnant women, depending on age
Not only exercise and stressful situations have a significant impact on glucose. A person’s age, gender, and a special physiological state of the body, which can be, for example, pregnancy, can significantly affect.
The concentration of carbohydrates in a pregnant woman is normally much higher than in a normal state, which is associated with the exertion of a large load on the body, requiring an intensification of metabolic processes.
In pregnant women, the analysis for carbohydrate content is carried out at least twice during the entire period of gestation. The first measurements are taken in the period from 8 to 12 weeks, and the second measurement is taken at 30 weeks of gestation.
Studies have established that the normal content of carbohydrates in plasma for a future mother is:
- 9-6 mmol / L for biomaterial from the capillary network;
- 7 mmol / L in the analysis of venous blood.
If there are deviations, a study is carried out using a glucose tolerance test. In some cases, a fructosamine test or a study that determines the amount of glycated hemoglobin can be used.
Normal indicators in men and women who are not carrying a child are the same, but in children, the norm depends on the age of the child and is:
- Age up to a year – 2.8-4.4 mmol / l.
- From one to 5 years old – 3.3-5.0.
- At the age of over 5 years, the child’s data correspond to an adult and range from 3.3 to 5.5 mmol / L.
Changes in the amount of glucose can be observed throughout a person’s life. The older a person becomes, the more the lower and upper indicators shift upwards.
Depending on the age of the subject, the following amount of glucose in the body is considered normal when examining the biomaterial from the capillary network:
- children under one year old – 2.8 mmol / l;
- children under the age of 14 – 2.8-5.6 mmol / l;
- men and women in the range from 14 to 59 years old – 4.1-5.9 mmol / l
- elderly people over 60 years old – 4.6-6.5 mmol / l.
The amount of glucose in the body also changes throughout the day:
- In the morning on an empty stomach, the norm is 3.9-5.8 mmol / l.
- An hour after eating – up to 8.9 mmol / l.
- Before lunch – ranges from 3.9 to 6.1.
- Before dinner, the level is 3.9-6.1.
- At night, between 2 and 4 o’clock, it fluctuates around the 3.9 mmol / l mark.
For the human body, both an increase and a significant decrease in the level of carbohydrates is a dangerous condition.
Interpretation of analysis results
If, as a result of a clinical study, the presence of a plasma sugar concentration in the range of 5.6-6.0 mmol / L is revealed, then the doctor assumes that the patient has a prediabetic condition. If these indicators are exceeded, men and women are diagnosed with diabetes mellitus.
To confirm the suspected diabetes, the patient is assigned a second study. In addition, an analysis is carried out to identify quantitative indicators of glycosylated hemoglobin.
In some cases, glucose exercise tests are done. Before testing, an empty stomach is taken to determine the baseline value.
After obtaining the initial indicator of the glucose content, the test to determine the glycosylated hemoglobin is carried out in the following way:
- 75 g of glucose is dissolved in 200 ml of water, the patient drinks the solution;
- after 30 minutes, one hour and two hours, material is collected for repeated analyzes.
Blood is drawn from a vein. When conducting a test with a child under 14 years of age, the amount of glucose is calculated as 1.75 g per kg of body weight.
The endocrinologist is engaged in decoding the analysis results. The value of carbohydrates before taking the solution should be normal or lower. In the event that the value of glucose tolerance is impaired, then intermediate tests indicate the presence of glucose concentration in the blood vein in the aisles of 10.0 mmol / l, and for plasma from the capillary network 11.1 mmol / l. If, after two hours, the test results are abnormal, then this indicates that glucose is not absorbed in the body.
For the human body, situations are dangerous when the level of carbohydrates is both overestimated and underestimated.
Consequences of a significant level deviation from the norm
In the male and female body, the level of carbohydrates from the venous bed and capillary network may fluctuate slightly, with minor deviations.
Most people are aware of the dangers of high glucose levels. But the reduced value is not given due attention. A lack of glucose can be even more dangerous than too much glucose.
Falling below the permissible level can provoke a whole chain of changes in the body. In order to control these physiological data one should undergo regular examinations. This is especially true for people who have a regular occurrence of hypoglycemic conditions.
In medicine, the following critical values of the carbohydrate content and their consequences are distinguished:
- Decrease less than 3.5 – increased sweating appears, heart contractions become more frequent, the patient feels hungry and lethargy.
- Decrease from 2.8 to 2 – the patient has disorders in behavior and mental activity.
- When falling to 2-1.7, serious disturbances in the work of the central nervous system appear, severe fatigue and lethargy are revealed, in some cases the patient is not able to give his own name.
- In the case of a decrease to 1, the patient develops convulsions and disorders are recorded in the brain on an encephalogram. Prolonged stay in this state leads to a coma.
- If less than 1 – irreversible processes occur in the brain, the person dies.
Increasing sugar is no less dangerous than lowering it. With an increased glucose content:
- the patient feels tired, weak throughout the body and headache;
- a person has a decrease in weight, despite having a good appetite;
- there is a frequent urge to urinate;
- the formation of pustules on the body is recorded, which are difficult to heal;
- the functional capacity of the immune system decreases;
- there is a feeling of itching in the groin area;
- in middle-aged men, potency disorder is recorded;
- visual impairment is observed.
It should be remembered that the increased content in the body may be the result of drug therapy with the use of nicotinic acid, diuretics, corticosteroid drugs and Indomethacin.
If, after taking blood from a finger or vein, a deviation from normal values in one direction or another is recorded, then you should immediately seek