What Is Puncturing a Vein to Draw a Blood Sample

Most To save a patient in a life-threatening situation the art of obtaining intravenous access should be mastered. Through this article, we help you understand the basics of venipuncture.

To understand venipuncture we need to know the field it is associated with. It is a part of the procedure called: Phlebotomy.

Phlebotomy - The Process Of The Collection Of Blood.

• It can be carried out by following any one out of the several methods like venipuncture.
• It is used for medical testing, to diagnose and treat a patient. It determines cholesterol, calcium and blood sugar level etc.
• The drawing of blood for treatment purposes is called therapeutic phlebotomy. This is conducted in conditions like hemochromatosis and erythrocytosis among others.

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The Methods Which Can Be Adopted To Collect Blood Are:

Capillary/finger stick sampling

• The sample is obtained from a fingertip in adults and the heel in infants.
• It is a fairly painless procedure.
• Example – Routine blood sugar testing by glucometer

Arterial sampling

• The blood sample is collected from an artery.
• It is conducted for arterial blood gas analysis.
• It checks oxygenation and the patient's ventilation status .

Venipuncture sampling

• It is carried out to obtain blood which can be for

1. diagnostic purposes- phlebotomy.
2. use in transfusion.
3. removing excess levels of iron in the body.
4. monitoring levels of specific components in blood.

• It is conducted also for the administration of medications or nutrition etc.
• It is favoured over arterial sampling as the walls of veins are thinner and easier to pierce.

What is Venipuncture?

It is the act of puncturing a vein as a part of a medical procedure.

• This facilitates obtaining intravenous access for the purpose of blood sampling.
• Also, it aids in intravenous therapy with fluids or medication for extended periods.
• It is the most commonly adopted method for phlebotomy procedures.

Let us discuss the procedure outline:

Prepare the patient

• Check the patient identification details.
• Verify the purpose of sample collection on the test report form.
• Make a note of the patient's general conditions and do observe vital signs throughout the procedure.
• Clean the site with antiseptic and allow it to dry completely.

Labelling

• Label all the tubes with the patient's particulars.
• All packets for transportation should carry legible labels.

Practice all precautions

• Wear gloves and PPE.
• Use
  • sterile needle/cannula.
  • sterile cotton swabs to disinfect the skin.
  • surgical spirit to wipe the puncture site.
  • clean tourniquet to assess the location of the vein.
• Arrange sterile specimen bottles.

Drawing blood

• Put an elastic band / tourniquet around the arm, 3-4 inches above the chosen site.
• The most suitable site for the collection of blood is the antecubital fossa, in the inner elbow area of the forearm.
• Ask the patient to close the fist.
• This will result in pressure that makes the vein swell with blood.
• Anchor the vein and make the skin taut 1-2 inches below the venipuncture site.
• Insert the needle with the bevel side up at an angle usually 15 to 30 degrees with the surface of the arm.
• Now perform venipuncture– draw blood.
• Collect blood in the tubes designated for the same.
• Tubes are colour-coded depending on additives in them for preserving the specimen.
• Tubes with anticoagulants should be inverted completely to facilitate complete mixing. This prevents the formation of any clots.

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Hemostasis

• To restore blood pressure, ensure that bleeding stops.
• Remove the tourniquet as the last amount of blood is drawn.
• Slowly withdraw the needle, and cover the site of the puncture with a bandage.
• Keep applying mild pressure till bleeding stops.

Disposal

• Dispose off all sharps in specified containers.

Delivering specimen

• Place specimens in leak-proof, biohazard packets for transportation.
• Samples collected outside the laboratories should be promptly delivered to the laboratory for interpretation.

Things to remember

Here are some key points to be kept in mind while performing venipuncture .

• Use a new needle for every draw.
• Blood volume collection should be minimum. It varies with the age of a patient. It should not exceed 3-5% of the total blood volume.
• Do not place the tourniquet too tightly.
• It should not be held in place for more than 2 minutes to avoid any haemoconcentration.
• Always use a disposable band to prevent transmission of infection.
• Apply it just before starting the venipuncture procedure.
• Avoid the site for carrying out the puncture if it is scarred or burned. If the arm has a cannula or IV infusion, it should not be selected for puncture.

Importance Of Venipuncture For Phlebotomists

For a phlebotomist drawing blood samples is essential for the diagnosis of illness and adverse health conditions. Venipuncture is important for the technicians as:

• It is a faster method of collecting samples as compared to the capillary method.
• It allows multiple collections to be done. The technician can collect samples for various tests by performing a single puncture.
• Some tests can only be performed on venous blood. The presence of disease in a gland is tested by venous blood sampling.
• Veins have less muscular tissue than arteries. This facilitates phlebotomists to perform venipuncture with ease.
• There is less likelihood of any contamination with tissue fluids.
• In case of an episode of bleeding, it can be stopped quickly. The blood pressure in veins is lesser than in arteries.
• It is an important skill to be mastered in their career.
• The physicians and laboratorians depend on phlebotomists for quality samples to be collected. This aids the doctors to reach an accurate diagnosis, and thus devise the best treatment plan for the patient

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FAQs

Procedure in which a needle is used to take blood from a vein.

It is used to take blood from a vein for blood analysis.

Usually for laboratory testing. Also, it is carried out to remove extra blood cells from the blood to treat certain disorders.

 The three popular methods of blood collection are:

• Sample collection from the arteries – Arterial sampling
• Sample collection from veins is called the venipuncture method of collection.
• Fingerstick sampling.

The needle should be inserted at an angle of 15 to 30 degrees formed with the surface of the arm.

The median cubital vein in the antecubital fossa is the preferred vein for Venipuncture.

What Is Puncturing a Vein to Draw a Blood Sample

Source: https://www.virohan.com/blog/what-is-venipuncture-why-is-it-important-for-phlebotomists/

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