Take blood from your finger. Why is blood taken from the ring finger from an anatomical point of view? Preparing for a fingerprint test. Determination of blood count: why is it needed

A blood test is the most common laboratory test, which is prescribed for preventive examinations and practically at any visit to a general practitioner. Most often, a general (clinical) analysis is required. In this case, donate blood from a finger. The algorithm and rules for passing are well known to everyone, without exception, from childhood. Everyone knows that the test should be taken in the morning, always on an empty stomach. The procedure is very simple, and the result is usually ready the next day.

Why do they take capillary blood?

Blood sampling from a finger is performed in the following cases:

• in general analysis to determine the cellular composition;
• to determine the glucose level (in this case, blood is taken from the vein, while the sugar level will be slightly different, which is normal);
• express analysis to determine the level of total cholesterol (venous blood is required for a more detailed study).

Preparation rules

1. To donate blood from a finger, you need to come to the laboratory in the morning (usually collection takes place from 7.30 to 10 hours).
2. The analysis must be taken on an empty stomach, that is, you cannot eat in the morning, you can only drink plain water. The last meal should take place the night before - no later than 8-12 hours before the procedure.
3. In the day before, you can eat, but it is recommended to give up fatty foods and alcoholic beverages a day or two before the analysis, so as not to get distorted results.
4. Physical and emotional stress should be avoided the day before.
5. In the morning before the procedure, you should refrain from smoking.

General analysis

Capillary blood collection from a child

In the expanded analysis, other indicators are added, including:

• hematocrit;
• red cell distribution width;
• average erythrocyte volume;
• the average content of hemoglobin in the red cell;
• leukocyte formula and others.

Instruments

Many people are worried about their own safety during the analysis, so they may have a question about what they pierce and how they take blood. Today, almost all medical institutions have switched to the use of disposable finger lancing devices. This tool is called a scarifier. It must be removed from the unopened package in front of the patient. It should be said that such a puncture is quite painful to make, so the procedure is very unpleasant for children.

Donating blood today can be painless. Increasingly, a new device is used when taking blood. This is an automatic lancet in a plastic case. The needle quickly pierces the skin, so no pain is felt. The new lancets have many benefits:

• a sterile needle or blade is located inside the body, which ensures the safety of patients and medical personnel;
• the reliability of the trigger eliminates the accidental exit of the needle or blade;
• reuse is excluded, thanks to the automatic return of the needle or blade;
• the shape of the needle provides a reduction in the pain effect;
• the puncture is targeted, its depth is controlled;
• convenient body shape.

Fence Algorithm

For work, the laboratory assistant must prepare:

• sterile scarifier;
• cotton wool;
• alcohol;
• tincture of iodine;
• ether.

Disposable scarifier - finger puncture instrument

The algorithm and technique for taking is as follows:

1. The patient sits opposite the laboratory assistant. The hand (usually the left) rests on the table.
2. The puncture site is disinfected with alcohol and degreased with ether.
3. A disposable scarifier quickly makes a puncture in the pad of the ring finger, immersing the instrument to the entire depth of the cutting part (by about 2-3 mm).
4. The first drop of blood is removed with dry cotton wool.
5. For the study, the second and next drops of blood are used, which are collected using a glass adapter, then placed in test tubes and signed.
6. After the blood has been taken, the injection site is treated with alcohol or iodine and clamped with a cotton swab until the blood stops completely.

The algorithm for taking capillary blood from a child is exactly the same as that of an adult.

Why from the ring finger?

Perhaps someone is interested in which finger the blood is taken from and why. The fence comes from the ring finger, although it is allowed from the middle or index. A puncture, like any violation of the integrity of the skin, can lead to infection. The ring, index and middle fingers have an isolated inner membrane, so in case of penetration, the infection will first be localized, which means there is time to eliminate it. The big and little fingers are directly connected to the shell of the hand, and when infected, the infection spreads to the entire hand. The choice of the ring finger is explained by the fact that it carries the least physical activity.

What does the analysis show?

Taking blood from a finger is for prophylactic purposes, for diagnosis and control of treatment. This is a basic examination, and the main characteristics most necessary for doctors, which the blood shows, are as follows:

• hemoglobin level;
• the level of red blood cells;
• the level of leukocytes;
• the relative content of lymphocytes, monocytes, neutrophils, basophils, eosinophils.

Blood sampling with an automatic lancet

With the help of clinical analysis, doctors can diagnose the following pathological conditions:

• leukemia;
• anemia;
• coagulation disorders;
• the presence of an infectious or inflammatory process in the body.

Interpretation of results

Decryption should only be carried out by the attending physician. You should not try to do this on your own based on tables that indicate the rate for each indicator. The doctor evaluates the main parameters not only individually, but also in the aggregate.

1. Hemoglobin level... The norm for women is 120-140 g / liter, for men - 130-160 g / liter. If the content is higher than normal, dehydration, intestinal infections, congenital heart disease are possible. A low level indicates anemia.
2. CPU (color index)... The norm is from 0.85 to 1.15%. Low values ​​indicate anemia, increased ones are observed with a deficiency of folic acid, with stomach cancer.
3. Red blood cells. The norm for men is 4-5 g / l, for women - 3.7-4.7 g / l. An increase in the level indicates renal pathologies, tumors, Cushing's syndrome. A slight excess of the norm can be observed with diarrhea, taking diuretics, burns. Low levels indicate anemia, overhydration, and blood loss.
4. ESR. Red cell sedimentation rate is an indicator of the level of plasma proteins. Normally, for women - up to 20 mm / hour, for men - up to 15 mm / hour. A high level is typical for inflammatory processes, infections, autoimmune diseases, intoxication, endocrine, renal and hepatic pathologies, and oncology. The reasons for the decrease are circulatory failure, hyperbilirubinemia, erythremia.
5. Leukocytes. The norm of white cells is 4-9X10⁹ / liter. The reasons for the decline are cancer with secondary tumors in the brain, diffuse connective tissue diseases, typhoid fever, viral hepatitis, leukemia. An increased level is observed in bacterial and fungal infections, acute inflammation, purulent infections, in pneumonia, otitis media, pancreatitis, bronchitis, meningitis, and so on.
6. Platelets. The normal content of platelets responsible for blood clotting is 180-320X10⁹ / liter. High platelets indicate the development of rheumatoid arthritis, polycythemia, tuberculosis, myeloid leukemia. The reduced content accompanies thrombocytopenic purpura, aplastic and hemolytic anemia, hemolytic disease, lupus erythematosus.

What blood is better to donate for analysis - venous or capillary?

Outwardly, blood from a vein and from a finger is slightly different. Venous - darker blood, capillary - light blood. Patients are often interested in why they take a venous one, if it is easier and more convenient to take it from a finger. It is believed that the best laboratories in the world work with venous, and its study using new methods gives more accurate results.

Finally

A fingerprint test is a fairly informative method, although it reflects only the general condition of the body. Deviations from the norm of certain indicators cannot be considered confirmation of the presence of any diseases. Changes in the composition of the blood allow one to suspect a developing pathology and undergo a specific examination at an early stage, when there are no symptoms. The result can be distorted if you do not follow the rules and donate blood not on an empty stomach, but after eating. In this case, re-analysis is prescribed.

Any change in the human body is necessarily reflected in the biochemical composition of the blood. Therefore, to identify violations or in the treatment of any disease, a general blood test is periodically performed. The doctor may prescribe a blood sampling from a vein, however, much more often, for basic studies, they use a blood sample from a finger (when a minimum amount of blood is sufficient for diagnosis).

How to prepare

No complicated preparation is required, but you still have to fulfill a number of requirements:

• A blood test is taken only on an empty stomach so that the results are objective and correct. The only thing that is allowed is drinking clean water;
• There should be no alcohol breakdown products in the blood, so you should refrain from drinking for at least 2 days;
• Fried and fatty foods also have a negative effect, the diagnosis will be more accurate if you stop eating it a couple of days before the test;
• Doctors do not recommend exercising before taking blood, which promotes the release of large amounts of hormones. They can provoke errors in the analysis results.

If you plan to donate blood at a state clinic, you will have to take with you a disposable scarifier (a device for piercing a finger), as well as medical gloves - sterile or non-sterile.

This point is very important, since many infectious diseases are transmitted through the blood. If the technician does not change the gloves after the previous test, but only washes and wipes them with alcohol, microscopic blood particles may remain on them. When taking an analysis, the hands of a medical worker are actively in contact with the injection wound, so infection can occur.

How a blood test is taken in a laboratory

Blood sampling is most often done from the ring finger. There is a scientific explanation for this - anatomically, the vessels of the ring finger are located somewhat isolated from the rest, so only this part of the hand will suffer if there is a danger of infection.

The puncture site is wiped with a cotton swab with 70% alcohol solution or other disinfectant. The laboratory assistant makes a puncture about 2-3 mm with a scarifier, after which he removes the first drop with a piece of cotton wool or a cotton pad. Subsequent portions are inflated using a small pear and glass adapter. The resulting blood is placed in glass tubes and signed.
After the injection, the injection site may bleed slightly, so it is better not to remove the cotton wool moistened with alcohol for a while.

What the general clinical analysis shows

General analysis is a basic study that can be prescribed even for preventive purposes. Often it is carried out in order to assess the effectiveness of the quality of therapy during treatment. However, when diagnosing diseases, a blood test will be one of the paramount, basic indicators. Here's what he shows doctors:

• the number and rate of erythrocyte sedimentation;
• hemoglobin level;
• the number of leukocytes, as well as the leukocyte blood count.

An analysis of blood taken from a finger can reveal such disorders as anemia, leukemia, clotting disorders, infectious and inflammatory diseases. However, if necessary, this analysis can be subjected to more detailed studies, for example, an allergen test.

The main indicators of the main fluid of the human body: leukocytes, platelets and erythrocytes, can tell an experienced doctor a lot. How much they are contained in a person depends on his health and well-being. Consequently, such a seemingly simple analysis can show diseases and disorders in the functioning of the body.

A clinical blood test is considered the most demanded laboratory examination prescribed for diagnostic purposes, for the prevention and control of pregnancy and the health status of patients. any age.

To obtain results, you need to donate blood from the capillaries of the finger for a general analysis. The rules and algorithm for sampling are well known to every person. The doctor reminds every year that the analysis must be taken in the morning and always on an empty stomach, and you can eat only after taking a sample. This manipulation is quite simple, and the answers from the laboratory can be taken the next day.

Laboratory examination

What does the analysis show?

In addition to a clinical blood test (cellular composition), a biomaterial from a finger is taken in such studies:

• To find out the concentration of glucose (sugar). It should be said that the index of capillary blood differs from the results of biochemical analysis. which is taken from a vein;
• To perform a rapid hematological analysis of cholesterol levels;
• For general examination before donation;
• To detect many diseases, such as cancer, HIV infection, hepatitis, anemia, etc. (rapid tests).

How should you prepare?

Recommendations

They come to the hospital for testing in the morning (usually from half past seven to eleven in the morning). Many patients are interested in the question: is it possible to eat before donating blood? As you know, the collection of blood fluid should be performed on an empty stomach. It is only allowed to drink plain water. The interval between the last meal and blood donation should be at least 10 hours.

Only light food may be eaten the day before the procedure. The fact is that eating too fatty foods that are heavy on the stomach, especially before bedtime, will lead to the analysis showing poor results. When preparing for the study, do not consume alcohol-containing drinks.

Important! Patients should try to avoid mental and physical stress before taking a sample. Smokers should forget about this habit in the morning before going to the laboratory.

The analysis cannot be taken if a week has not passed after such procedures: X-ray, radiation, chemotherapy.

For children, the rules are more flexible. Parents often wonder if children need to donate blood on an empty stomach. You should not refuse to feed a newborn baby or baby. In addition, the formula and breast milk are quickly absorbed and will not lead to a large difference in the analysis parameters.

What does a complete blood count from a finger show?

UAC can be expanded or shortened. The abbreviated version includes the following parameters:

• The value of platelets;
• Erythrocytes;
• Hemoglobin;
• Leukocytes and their individual types (neutrophils);
• Lymphocytes;
• ESR (formerly - ROE) - erythrocyte sedimentation rate.

For a detailed study, additional data are considered:

• Hematocrit;
• Sugar level;
• Cholesterol content;
• The magnitude of the distribution of red blood particles;
• Average red blood cell count;
• Leukoformula.

Research instruments and devices

Many patients are concerned about how painless and sterile the procedure is. Today laboratories use disposable instrument kits that are sold in pharmacies. The device for piercing the skin on the finger is called "scarifier". The package with this instrument is opened by the nurse - this needs to be done only in front of the patient. Sometimes the puncture is very painful, so many children (and often adults) are afraid of this procedure.

Puncture photo

However, in modern clinics, new devices are used for painless sample collection - these are automatic lancets with a needle in a plastic container. The needle quickly penetrates the skin of the finger, and no pain is felt. These lancets have many advantages:

• Guaranteed sterility (it is impossible to reuse the instrument);
• Reliability of the technique for taking blood from the capillaries of the finger (accidental needle exit is excluded);
• The shape of the needle does not lead to painful effects;
• Suitable for home use;
• The puncture depth is adjustable;
• The body has a comfortable shape.

The video below describes the use of the lancet:

Sampling Algorithm

Blood collection begins with the preparation of instruments:

• Sterile device;
• Cotton wool;
• Iodine solution;
• Alcohol;
• Ether

The man sits down opposite the nurse, puts his hand on the table. The puncture site is preliminarily wiped with alcohol and ether for degreasing. A puncture is performed using a blood sampling device from the ring finger. The instrument is immersed approximately 2 millimeters into the skin.

The first blood drop is removed with a cotton swab, and the rest are used for examination. They are collected in a glass container, and then sent to test tubes and smears are made. After taking blood, the finger is disinfected again, treated with iodine solution and applied with a cotton swab until the bleeding stops.

Why exactly the ring finger?

Usually a puncture is made in one of the middle three fingers. The little finger is not suitable for these conditions. The fact is that any wound can cause infection. And these three fingers have their own inner shell, so that if an infection enters, microorganisms will be localized and eliminated before entering the bloodstream. The thumb, like the little finger, is directly connected to the skin of the hand. If penetrated, the infection can spread throughout the arm.

What is the blood sample taken from the puncture on the finger?

Clinical research can help diagnose various diseases and conditions:

• Leukemia;
• Anemia;
• Helminths;
• Gynecological diseases;
• Coagulation disorders;
• Dangerous infections, such as syphilis;
• Inflammatory processes;
• Agglutination of erythrocytes.

Decryption

Only the attending physician can decipher the survey answers presented in the form with the table.

Attention! You do not need to do this at home on your own, relying on generally accepted norms. After all, the doctor can assess not only each individual indicator, but also compose a cumulative picture of the patient's health.

UAC alone is not enough to identify serious diseases, so the doctor may ask you to take urine and blood from a vein for biochemistry.

A fingerstick test is a method of taking a biological sample that is used if the test requires a small amount of blood.

How to take

The method for studying capillary blood is quite informative and simple. However, in order to obtain the most reliable results, the following rules must be observed:

• Blood from a finger should be taken in the morning on an empty stomach (8-9 hours after the last meal).
• On the eve of the analysis, it is not recommended to visit the bathhouse, sauna, as well as overload the body with excessive physical training.
• Before the analysis, it is allowed to drink only a small amount of plain water without gas.
• If the patient is taking medications, he must definitely notify the doctor who gives him a referral for research. This is due to the fact that some medications can distort the analysis results.
• The day before taking a blood test from a finger, you should stop drinking alcohol.

Do not rub your fingers before the procedure. Such an action can provoke an increase in the level of leukocytes in the blood, which will also negatively affect the test results, and incorrect test results often cause an inaccurate diagnosis.

Decryption

Consider some indicators of a clinical blood test:

A clinical or general blood test from a finger is performed not only for the purpose of diagnosing pathologies, but also for prevention. A timely study allows the specialist to identify the disease at an early stage of development and prevent many possible complications.