Is it possible to take a general blood test from a vein?

Indications for analysis

As a rule, blood for a general blood test is taken from a finger. But in some cases, a blood test from a vein is prescribed to conduct the study. This happens when the purpose of a laboratory test is to identify a large number of parameters for which there is not enough blood from a finger. Also, more blood is needed to detect some types of infections.

In addition, venous blood differs in composition from capillary blood - that which is taken from a finger. So, it contains more glucose, and in many situations this is important for a more accurate diagnosis.

What do you use to prick your finger when taking blood? why do you need to donate blood from a finger prick?

A blood test is the most common diagnostic procedure. It is carried out at absolutely any age, as part of a comprehensive examination. An analysis in which blood is taken from a finger is called a general test.

In order for the result to be most reliable, the main principles of preparation and implementation of the procedure should be observed.

Why is blood taken from a finger?

What does a general blood test show? As a result, the study determines the number of certain types of blood cells. This is necessary for diagnosing various diseases.

The main functions of general analysis include:

  • Hemoglobin level measurement,
  • Platelet count,
  • Determination of blood clotting abnormalities,
  • Determination of the number of monocytes and lymphocytes,
  • Measurement of the number of neutrophils, basophils and eosinophils,

The results obtained help determine the development of diseases such as:

  • Anemia,
  • Bone marrow diseases,
  • Infectious or inflammatory diseases,
  • Development of an allergic reaction,
  • Diabetes,
  • Cardiovascular diseases,

How to prepare properly?

The analysis will show a reliable result only if you prepare for it correctly. Is blood donated on an empty stomach or not? Treatment rooms in government institutions are open strictly in the morning. You cannot have breakfast before taking blood. In private clinics you can donate blood at any time.

The main principles of preparing for blood collection are as follows:

  • The day before, he recommends avoiding foods rich in fats.
  • You should not drink alcohol 1-2 days before donating blood.
  • Immediately before visiting the treatment room, you should refrain from smoking,
  • It is recommended to avoid stressful situations and physical activity the day before,

Types of blood sampling instruments

It is advisable to first find out how blood is taken for research. The degree of pain depends on the device for drawing blood. This function is performed by a scarifier for drawing blood. It is a thin steel plate with a pointed end. During the procedure, a puncture is made on the skin of the finger, through which blood flows out.

For children, a special device is provided that allows blood sampling to be done painlessly. It is called a lancet . The piercer is a special needle placed in a certain way, providing uniform pressure on the skin. Using the lancet is quite simple. The device works by contacting the skin or pressing a special button.

Taking blood from infants also does not cause any difficulties . For this purpose, you can use the Komarik kit for painless delivery. The set comes with 4 disposable needles. The mechanism of the device allows you to pierce with a needle without pain so that the child does not understand anything.

The advantages of a lancet over a scarifier are as follows:

  • Speed ​​of use,
  • The possibility of hematomas at the puncture site is excluded,
  • No pain
  • Can be used at home,
  • The appearance of the device does not cause emotional stress, which helps to obtain reliable results,

Procedure implementation process

How to take blood from a finger at home

To obtain the most reliable results, the puncture technique must be followed. Blood donation is carried out in a specially equipped sterile room. It is important to pay attention to the instrument used to prick when drawing blood. It should be disinfected.

The following items are required:

  • Alcohol or other antiseptic,
  • Piercing needles or scarifier,
  • Glass for taking a smear,
  • Iodine tincture,
  • Ether,

The procedure algorithm is as follows:

  • The upper phalanx of the ring finger of the left hand is treated with an antiseptic,
  • The tool is directed strictly from the side, at an angle,
  • The next step is to pierce the finger. When a drop of blood appears on the surface of the skin, it is removed with a sterile swab,
  • A second drop of blood is used for the test.
  • The blood collection method involves making smears. For this purpose, sterile glasses are used,

Which finger is best to take blood from?

Why is it common to take blood from the ring finger? The choice is due to the fact that this finger bears less physical stress. Injury to the damaged area of ​​skin is unlikely. You can also take blood from your middle or index finger. This is practiced if plasma donation is carried out on a regular basis.

Any damage to the skin can lead to the spread of infection. The anatomical location of the index, middle and ring fingers eliminates the possibility of infection spreading to the hand due to the presence of an internal septum. Infection from the little finger or thumb spreads faster.

What is the difference between venous blood sampling and capillary blood sampling?

Rules for collecting capillary blood

Why do venous blood sampling if capillary blood donation is much easier? Venous blood analysis is more detailed. Even externally, there are significant differences between capillary and venous blood. The first is quite light, and the blood from the vein is dark. In laboratory conditions, it is much easier to work with a venous blood sample.

What is detailed analysis?

A comprehensive blood test is called a biochemical blood test. Blood taken from a vein is examined. It is prescribed when clinical analysis does not provide enough necessary information.

The advantages of this type of analysis are as follows:

  • Accurate diagnosis of the disease,
  • The ability to determine the level of vitamins in the body,
  • The ability to identify the disease at an early stage, in the absence of characteristic symptoms,

Despite the fact that the general analysis shows less information, it also has its advantages.

These include the following:

  • High speed of the procedure,
  • Only pierce the skin surface. The depth of the wound does not exceed 3 mm,
  • The fence rules are much easier to follow. This increases the reliability of the result,
  • Capillary biomaterial is tested much faster than venous blood,
  • In private clinics, the price for a general analysis is lower than the cost of a biochemical one,

Where to submit?

Doubts regarding your health sooner or later make you wonder how and where to take a general blood test. The answer to this question depends on the patient's requirements and capabilities.

There are three possible options:

  • State clinic,
  • Private clinic,
  • Medical personnel visiting your home,

In the first case, the diagnostic procedure is carried out within the framework of health insurance. The analysis is absolutely free . The disadvantages of donating blood at a government institution include long queues and the procedure being carried out at a strictly fixed time. It takes more time to examine a blood sample, which cannot be said about private clinics.

You can take the test at a paid institution at any convenient time. The main condition is not to eat for more than 3 hours. It costs more to have a medical professional visit your home. The advantages of the service include the absence of the need to leave the walls of the house, which is especially important if the patient is seriously ill.

Analysis results

You can find out how much analysis is done immediately before donating blood. Typically, the duration of the study is from 5 to 7 days . In private clinics, the result is ready within 3-5 days after the collection procedure.

If you get bad results, you should remember the following:

  • The possibility of error cannot be ruled out
  • The reliability of the result depends on how correctly the medical worker takes the blood,
  • Violation of the rules for preparing for analysis leads to an incorrect result,
  • Before the procedure, do not rub your fingers. The resulting result will include increased white blood cell counts,

The results are interpreted by the attending physician. Self-medication is strictly prohibited.

  • General blood test norms
  • As a result of the analysis, data on the following parameters are presented:
  • Hemoglobin,
  • red blood cells,
  • Reticulocytes,
  • platelets,
  • ESR,
  • Leukocytes,
  • Monocytes,
  • Lymphocytes,
  • granulocytes,
  • color index,

A person who has passed a general analysis has a question about what result should be feared.

The following situations indicate the presence of serious diseases:

  • Drop in hemoglobin level
  • Increase in ESR,
  • Increase in the number of leukocytes,
  • Reduction of red blood cells,


Preparing for analysis

To prepare for the study of blood from a vein, it is enough to refrain from eating heavy fatty foods and alcohol on the eve of the test. A blood test from a vein is taken on an empty stomach, usually in the morning. You should not eat for at least two to three hours before visiting the laboratory. But this applies specifically to a general blood test. Some tests have stricter rules. For example, before a biochemical blood test you cannot eat for 8 hours, and the time interval between the last meal and the moment of blood sampling to determine triglycerides in the blood must be at least 12 hours. Therefore, you should consult your doctor regarding preparation for the test.

Blood is drawn using a needle from the veins of the forearm or elbow. If these veins are not clearly visible, blood can be taken from the venous vessels of the popliteal cavity or the back of the hand.

general description

Despite the fact that a clinical or general blood test is traditionally taken from a finger, an increasing number of modern clinics, especially if the most complete, detailed clinical analysis is needed, prefer to take blood from a vein.

This is explained by the fact that a detailed clinical analysis involves the use of a significant amount of biofluid, which can be quite problematic to obtain from a finger, but very simply from a vein.

A detailed clinical blood test is prepared on ultra-modern, expensive analyzers, which require a fairly large amount of material for research.


And another argument in favor of taking blood from a vein rather than from a finger is that capillary and venous blood are quite different in composition.

The latter, for example, contains much more glucose, which can be very important for making a diagnosis for some diseases.

Thus, if a detailed analysis is needed, venous rather than capillary blood is preferable.

What is research? What is the difference between clinical detailed and ordinary tests?

A general blood test is a study of a person’s biofluid, aimed at identifying pathological processes in his body at the early stages of their development.

The analysis is carried out for both therapeutic and preventive purposes, as well as to monitor the progress of pregnancy.

Clinical fluid analysis provides information on various blood parameters.

Their number can range from 10 to 50. If the number of obtained parameters exceeds 30, this is a detailed general analysis.

READ Presence of atypical mononuclear cells in a general blood test

It is preferable to take a clinical test (either from a finger or from a vein) on an empty stomach, having previously given up too heavy (spicy, fatty, fried) foods 2 days in advance.


Taking a biofluid on an empty stomach is explained by the fact that if less than 6 hours before the test the patient eats (even if he just drinks sweet tea with cookies), this can greatly distort the results of the analysis.

If it is too difficult to eat nothing for a long time, it is still advisable to come to the laboratory on an empty stomach and remain hungry when donating blood, but take a snack with you so that you can have a snack immediately after the procedure.


Below are the main parameters of a general blood test, their standard designations used in many laboratories, and the norms for analyzing blood from a vein, as well as some explanations for deviations of the analysis from the norms.

  1. Hemoglobin (Hb) . The norm for men is 120–160 g/l, for women – 120–140 g/l. Low hemoglobin can occur after bleeding, as a result of anemia and some hereditary diseases.
  2. Hematocrit (Ht) . The norm for men is 40–45%, for women – 36–42%. This indicator indicates the percentage ratio of the number of blood cells (platelets, erythrocytes, leukocytes) to the volume of its liquid part - plasma. A low hematocrit occurs after blood loss, as well as in case of disruption of the formation of new blood cells, for example, in autoimmune diseases and acute infectious processes. An increase in this indicator may indicate dehydration.
  3. Red blood cells . The norm for men is 4.3–6.2 x 1012, for women – 3.8–5.5 x 1012. An increased level of red blood cells indicates the risk of red blood cells sticking together, which can lead to thrombosis (blockage of blood vessels). A low level of red blood cells in the blood indicates a lack of oxygen.
  4. Color Index (CPI) . The norm for this indicator is 0.85–1.05. Denotes the ratio of the amount of hemoglobin to the level of red blood cells. Deviations of the color indicator from the norm are detected in various types of anemia.
  5. White blood cells (WBC) . The norm is 4–9 x 109. This parameter of a general blood test can increase during infectious processes in the body and leukemia. A decrease in leukocytes may be a sign of a disruption in the process of their formation in the bone marrow, which may indicate autoimmune, oncological and acute infectious diseases.
  6. Neutrophils (NEU) . The norm is within 70% of the total number of leukocytes. A significant increase in the level of neutrophils usually indicates a purulent inflammatory process in the body.
  7. Eosinophils (EOS) . The normal content of eosinophils ranges from 1–5% of the total number of leukocytes. An increase in the level of eosinophils is typical in the presence of parasitic diseases, as well as allergic diseases.
  8. Lymphocytes (LYM) . The normal level of lymphocytes in the blood is 19–30%. An increase in the number of lymphocytes occurs during infectious diseases and blood diseases. A low lymphocyte count may indicate kidney failure, chronic disease, a weakened immune system, or taking medications that suppress the immune system.
  9. Platelets (PLT) . The norm is 170–320 x 109. A high level of platelets can be observed after operations and in some blood diseases. A decrease in platelet levels may be an indication of an acute inflammatory process or an immunological disease.
  10. Erythrocyte sedimentation rate (ESR) . The norm for this blood parameter for men is 10 mm/h, for women – 15 mm/h. An increased erythrocyte sedimentation rate is usually an indirect sign of some disorder in the body, for example, an inflammatory process.

Method of collecting venous blood

The technique of collecting venous blood requires compliance with conditions of strict sterility and the implementation of a certain sequence of actions.

  1. Prepare the container and direction to the laboratory, label it, indicate the patient’s data, enter the information into a journal or electronic system.
  2. Place the patient on a chair near the manipulation table. Fix your hand with your palm up in the position of maximum extension of the elbow joint. Place an oilcloth roller under the elbow.
  3. Apply a rubber or fabric tourniquet to the middle third of the shoulder; the pulse should be palpable at the wrist.
  4. Treat the elbow area with a cotton swab moistened with medical alcohol.
  5. Ask the patient to work intensively with his fist to maximally fill the cubital vein with blood, and then squeeze his fingers.
  6. Using a syringe or vacuum system, puncture the ulnar vein at an acute angle with the needle cut down until you feel it “falling” into the void. Then direct the needle parallel to the wall of the vessel. If necessary, veins from the wrist or hand can be used.
  7. Pull the syringe plunger up; when the needle enters the vein, dark cherry blood will appear inside the cannula. When using vacuum systems, the blood independently enters the tube under pressure.
  8. When taking the required amount of biomaterial, a cotton ball moistened with alcohol is pressed to the puncture site, and the needle is removed from the vein. When using vacuum systems, the tube must first be disconnected.
  9. The patient bends his arm at the elbow joint for 5 minutes to form a clot at the site of puncture of the vessel and prevent the formation of a subcutaneous hematoma.

When collecting blood for examination of a newborn child, it is often not possible to puncture the ulnar vein due to physiological characteristics. Therefore, for laboratory tests, veins are used on the head (in the fontanelle area), hand, forearm, and lower leg.

Labeled tubes are placed in a special container and sent to the laboratory. A day is usually enough to obtain the results of the study. In some cases, an examination must be carried out urgently to select treatment tactics for life-threatening conditions. In this case, the analysis is carried out in a few hours, and the “cito!” mark is placed on the referral form.

If the rules for collecting blood for research are not followed, infectious and inflammatory complications may occur. This condition is accompanied by pain in the arm, increased body temperature, and redness at the site of the puncture of the vessel. Violations in the general condition and local changes in the area of ​​​​the vein puncture require consultation with a doctor and the appointment of appropriate treatment.

Taking blood from a peripheral vein for laboratory examination is a simple but informative diagnostic method. It requires strict adherence to the rules of preparation for the study, collection of biological fluid, and transportation. This approach ensures the effectiveness of disease detection and therapy, eliminates false test results and the development of complications after the procedure.


Why do they take blood from a finger and what can it mean?

One common laboratory method is a blood test. It is prescribed at almost every doctor’s visit and blood is always donated during medical examinations. This research method is informative and accessible, thanks to which you can assess the condition of the body. A finger prick blood test in medical practice is called a general or clinical analysis.

Why do they take blood from a finger: the purpose of the procedure

A general blood test includes counting all blood cells and determining their parameters

Blood from a finger test allows you to diagnose sugar levels, the number of platelets, red blood cells, leukocytes and other blood cells. Decoding the data allows you to determine the presence of inflammatory processes.

A finger prick blood test helps identify various pathologies: bleeding disorders, anemia, leukemia, infectious diseases. If a malfunction occurs in the body, this is always reflected in the composition of blood cells. After treatment of any disease, a finger prick blood test is also prescribed to monitor and ensure the effectiveness of treatment.

Such an analysis is always given during pregnancy to assess the condition of the fetus and the mother’s body. The woman experiences significant stress, so some values ​​may deviate from the norm, but this does not always indicate pathology.

Each of the analysis indicators has its own meaning.

The purpose of the procedure depends on the age and condition of the patient. For children and adults, a blood test is performed to determine the child's general condition. The procedure may have a simplified or expanded version.

How to take blood from a finger

The procedure for collecting blood from a finger

On the day of the study, the patient comes to the medical facility early in the morning. He sits down opposite the laboratory assistant and puts his hand on the table. Next, the laboratory assistant treats the pad of the ring finger with an antiseptic and lightly dries it with dry cotton wool. Then the laboratory assistant punctures the finger with a disposable needle 2-3 mm.

The first drop of blood is removed with a cotton ball, and the next drops are collected into a special adapter.

During the procedure, the finger should not be squeezed, as blood may mix with tissue fluids and, as a result, the analysis will be unreliable.

The blood is placed in a test tube, which is pre-labeled.

After drawing blood, a cotton pad moistened with an antiseptic is applied to the puncture site. You need to hold it for about 5-7 minutes until the bleeding stops. This procedure is carried out for adults and children over one year old.

For newborn children, the procedure is slightly different. The puncture is made not on the toe, but on the side of the heel. To reduce pain in a child, automatic sterile lancets are used. The result can be found out on the day of blood donation, in some cases after 1-2 days.

How to prepare for the procedure

Getting ready for a finger prick blood test correctly!

Before donating blood from your finger, you need to prepare for the procedure. This is necessary in order to obtain reliable information. It is important to remember that results may vary under certain conditions.

Basic recommendations when preparing to take blood from a finger:

  1. Do not eat before the test. In the morning you can only drink water. Dinner should be no later than 8-10 hours before the procedure.
  2. The day before, you should avoid eating smoked, fried and spicy foods. All this affects the test results.
  3. The day before blood sampling, you need to avoid physical activity.
  4. Serious emotional shocks must be avoided.
  5. You must notify your doctor and laboratory technician about long-term use of medications. It is important to know that some medications can be stopped the day before the test, while others can be stopped a week before. The results may be affected by taking the following medications: antibiotics, aspirin, multivitamins, oral contraceptives, etc.
  6. It is not recommended to smoke a few hours before the test.
  7. It is not advisable to conduct ultrasound, MRI and other instrumental methods 24 hours before a blood test. They are safe, but radiation, ultrasound or electromagnetic radiation can have different effects on blood cells.
  8. Physiotherapy procedures may affect the clinical analysis, so it is better to carry them out after blood sampling.
  9. If a blood test is ordered while a woman is menstruating, the GP should be notified. It is also necessary to inform the doctor about the onset of pregnancy and menopause.

( 1 rating, average 5 out of 5 )
Did you like the article? Share with friends:
For any suggestions regarding the site: [email protected]
Для любых предложений по сайту: [email protected]
Для любых предложений по сайту: [email protected]