Venipuncture using a vacutainer.

In medicine venipuncture or venepuncture (also known as phlebotomy, venesection, blood draw, drawing blood or taking blood) is the process of obtaining a sample of venous blood. Usually a 5 ml to 25 ml sample of blood is adequate depending on what blood tests have been requested. In many circumstances it will be done by a phlebotomist, although nurses, doctors and other medical staff are also trained to take blood. Image File history File linksMetadata Blooddraw. ... Image File history File linksMetadata Blooddraw. ... In the circulatory system, a vein is a blood vessel that carries blood toward the heart. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... A phlebotomist is an individual trained to draw blood (venipuncture), either for laboratory tests, or for blood donations. ...

Blood is most commonly obtained from the median cubital vein, on the anterior forearm (the side within the fold of the elbow). This vein lies close to the surface of the skin, and there is not a large nerve supply. Superficial veins of the upper limb. ... // The Human Forearm The forearm is the structure on the upper limb, between the elbow and the wrist. ...

Minute quantities of blood may be taken by fingersticks sampling and collected from infants by means of a heel stick or from scalp veins with a butterfly needle. Butterfly needle Winged Infusion Sets, or Butterfly needles are very small needles used in venipuncture (phlebotomy) of very young or elderly patients or patients with small veins and arteries. ...

Phlebotomy (incision into a vein) is also the treatment of certain diseases such as hemochromatosis and primary and secondary polycythemia. Haemochromatosis, also spelled hemochromatosis, is a hereditary disease characterized by improper processing by the body of dietary iron which causes iron to accumulate in a number of body tissues, eventually causing organ dysfunction. ... Polycythemia is a condition in which there is a net increase in the total number of red blood cells in the body. ...

Equipment

There are many ways which blood can be drawn from a vein. The best method varies with the age of the patient, equipment available and tests required.

Most blood collection in the US and UK is done with an evacuated tube system, such as a Vacutainer system or similar blood collection equipment consisting of a plastic hub, a hypodermic needle, and a vacuum tube. Under certain circumstances, a syringe may be used, usually with a butterfly needle, which is a plastic catheter attached to a short needle. In the developing world, a needle and syringe are still the most common method of drawing blood. Different bevels on hypodermic needles. ...

Blood is usually drawn from a vein in the crook of the elbow, the antecubital region. Tubes have color-coded stoppers to indicate what type of anticoagulant or other substance is in the tube. Tubes may contain no additive, a gel substance which separates cells from serum, or a variety of anticoagulants or preservatives (e.g. sodium heparin, sodium citrate, sodium fluoride and potassium oxalate or potassium EDTA). An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. ... Heparin, a highly sulfated glycosaminoglycan is widely used as an injectable anticoagulant and has the highest negative charge density of any known biological molecule. ... Sodium citrate is the sodium salt of citric acid with the chemical formula of Na3C6H5O7. ... Sodium fluoride is an ionic compound with the formula NaF. This colourless solid is the main source of the fluoride ion in diverse applications. ...

Venipuncture with evacuated or vacuum tubes (vacutainers)

Vacutainers® are a type of test tube that contain a vacuum that automatically aspirates blood into itself. They are made of glass or plastic. They are commonly used in US and UK hospitals, private doctors offices and community labs, and are effective in most adult patients and older children. For infants or toddlers there are smaller size vacutainers available. A range of Vacutainer tubes containing blood. ...

Equipment needed includes: a plastic needle holder or "barrel", needles designed specifically for the needle holder, an adjustable tourniquet, appropriate tubes, alcohol swabs, 2x2 gauze pads (cotton balls used to be used, but they have been found to dislodge the clot and the patient bleeds again causing larger hematomas), sticky tape, and a pen for labeling. Look up needle in Wiktionary, the free dictionary. ... A tourniquet can be defined as a constricting or compressing device used to control venous and arterial circulation to an extremity for a period of time. ... Functional group of an alcohol molecule. ...

Below is a sample of the procedure used when blood is collected with Vacutainers.

1. First of all, the patient should be identified -- a test result is useless if it's done on the wrong person. The test subject should be asked their name and date of birth. This should not be a yes or no question, e.g. Are you Stanley Jones?, as many people will just agree, especially if they are elderly and have hearing difficulties or senility.
2. The vacutainer tubes needed for the tests required should be determined, and nearby ready to be used. The order that the tubes are used is important, and should be known before puncturing the skin. Other equipment that will or may be needed should also be handy.This includes foil or an amber tube to shield specimins from light, or ice or heat packs for temperature sensitive samples.
3. A tourniquet should be placed on the arm where blood is to be collected. This should be just tight enough that blood collects in the veins.
4. The vein to be used should be palpated; its depth, size and direction should be determined, and the best angle to puncture the skin planned.
5. The skin around the area should be wiped with an alcohol swab (or iodine prep if drawing for blood culture) and allowed to air dry. An appropriate needle should be placed into a holder.
6. The needle should be inserted into the vein with the bevel facing upwards. It should be pushed quickly and smoothly through the skin to minimize pain and to prevent blood from spouting out through the bevel.
7. Once the needle is in the vein, a vacutainer should be pushed into the needle holder. Care should be taken to ensure the needle does not move too much. The tube will fill itself up with blood.
8. The tube can be removed once full, and the next one pushed into the holder.For tubes that contain additives it is important to be sure that the minimum amount of blood is in the tube or the blood to additive ratio will not be correct. This can impact the suitability of the sample for testing. Some types of tubes such as Sodium Citrate, EDTA, Lithim Heparin, and Sodium Heparin must be mixed after drawing. This is done by inverting the tube seven times, NOT shaking the tube as this can cause hemolysis.
9. On the last tube, the tourniquet should be loosened or removed once blood starts to enter the tube. Make sure the tourniquet does not stay on longer than one minute.
10. The last tube should be removed from the holder before the needle is pulled from the vein.
11. The needle should be pulled out of the skin on the same angle it went in.
12. Once the needle is removed, clean gauze should be pressed onto the wound, and the patient instructed to apply pressure to it. Doing this may minimize bruising or echymoses.
13. The tubes should be well mixed by inverting them gently a number of times, and labelled straight away. The wound under the gauze should be checked, then the gauze or a adhesive bandage taped to the patient's arm.
14. The patient should be instructed not to lift heavy objects or perform strenuous activities for about 12 hours, otherwise bruising is likely to result.

To prevent cross-contamination of samples with additives from other tubes, it is necessary to insert and withdraw Vacutainer tubes in a set order, referred to by phlebotomists as the "Order of Draw." When drawing blood for very sensitive testing, it is sometimes advisable to first draw a red top (no additive) tube, which is then discarded, to eliminate from the sample the interstitial fluid that comes from the puncture site rather than from the bloodstream. Subsequent tube order is determined by the need to prevent a tube's contamination by additives used in a previous tube that might affect laboratory analysis. A range of Vacutainer tubes containing blood. ... A tourniquet can be defined as a constricting or compressing device used to control venous and arterial circulation to an extremity for a period of time. ... Palpation is a method of examination in which the examiner feels the size or shape or firmness or location of something (of body parts when the examiner is a health professional). ... Different bevels on hypodermic needles. ... A bruise or contusion or ecchymosis is a kind of injury, usually caused by blunt impact, in which the capillaries are damaged, allowing blood to seep into the surrounding tissue. ...

Venipuncture with needle and syringe

A syringe is used to manually extract blood from a patient. The very young, very old and anyone with problematic veins are all candidates for this old-fashioned method. Because syringes are manually operated, the amount of suction applied may be easily controlled. The procedure is similar to what is described in the section above. After the needle is inserted into the vein, the phlebotomist receives confirmation of success when a small amount of blood appears in the back of the needle. This is often referred to as 'flash'. The plunger is then pulled backwards and blood fills the syringe. If the syringe plunger is pulled back too quickly red blood cells may be broken (hemolyzed) by turbulence or physical forces as they are forced through the needle. The blood is usually transferred quickly to a vacutainer before clotting sets in using a similar defined tube order;normally the opposite of the order of draw when using a vacutainer. A syringe nowadays nearly always means a medical syringe, but it can mean any of these: A simple hand-powered piston pump consisting of a plunger that can be pulled and pushed along inside a cylindrical tube (the barrel), which has a small hole on one end, so it can... Hemolysis (alternative spelling haemolysis) literally means the excessive breakdown of red blood cells. ... Coagulation is the thickening or congealing of any liquid into solid clots. ...

Note on Blood Cultures

Most often, blood cultures are drawn using a "butterfly" needle. When drawing blood cultures, the aerobic culture should be drawn first. Aerobic means bacteria that grow in the air and Anerobic means that these are bacteria that do not grow in the air. Since there is air in the "butterfly" needle tubing you cannot collect an anaerobic specimen without first removing the air from the tubing. This can also be done by using an empty plain vacutainer and then discarding it. The tops of any containers used when drawing a blood culture should be sterilized with isopropyl alcohol.

Blood Alcohol Tests

Check with your employer, but it is not advisable to use isopropyl alcohol to cleanse the venipuncture site when obtaining a specimen for blood alcohol levels. Soap and hot water is an acceptable alternative to isopropyl alcohol when using venipuncture to collect blood sample for BAC tests.

See also

• Fingerprick
• Vacutainer
• Blood donation

In medicine, some blood tests are conducted on venous blood obtained by fingerprick. ... A range of Vacutainer tubes containing blood. ... “Give blood” redirects here. ...

External links

• Phlebotomy details