Venipuncture is the process of obtaining blood samples from veins for the purpose of laboratory testing.
The procedure is performed by phlebotomists, paramedics and medical laboratory scientists, to name a few.
Venipuncture is probably the most common procedure in the medical field; usually performed for either of the following reasons:
- To obtain blood samples in order to perform diagnostics
- To administer therapeutic treatments to patients
- To collect blood for later use should the patient’s condition requires transfusions
- To remove blood that was found with excessive levels of erythrocytes or iron
- To monitor the levels of various blood components
To perform venipuncture, a phlebotomist will need the following equipment:
Evacuated Collection Tubes: Tubes come in various sizes and are designed to fill with a fixed, predefined volume of blood by vacuum. Their rubber-made top is colored according to the additive contained in the tube. The colored top is meant to identify the uses of a particular tube. As a result, pouring blood from one tube to another is strictly forbidden.
Needles: Available for use with a syringe, a single draw or a butterfly system, needles come in various outer diameters. The metric used to describe the outer diameter of a needle is the gauge number. In principle, the larger the gauge number, the smaller the outer diameter of a needle. For a detailed needle gauge comparison, click here.
Note: A needle disposal unit is absolutely essential. After a needle has been used, it must be disposed immediately.
Gloves: Gloves play a major role in infection control. Every phlebotomist is required to wear gloves in order to protect both his patient and himself. Gloves are usually made of latex.
Phlebotomy Tube Holders: They are essential in preventing needlestick injuries during the disposal of sharps that follow a venipuncture procedure.
Tourniquet: Used to control venous circulation by applying pressure upon the skin in order to perform venipuncture. Tourniquets should be wiped off with alcohol prior to every use. It is also vital to replace it frequently.
70% Isopropyl Wipes and Providone – Iodine Wipes: The latter are being used when a blood sample collection is to take place.
Gauge Sponges: Applied in the selected venipuncture site after needle withdrawal.
Adhesive Bandages: Used to protect the venipuncture site after the blood draw.
Syringes: Used instead of the routine evacuated tube system if the patient has fragile and / or tiny veins that may not be able to withstand the vacuum pressure of evacuated tubes.
Biohazard Bag: To safely dispose equipment used in the procedure.
Venipuncture Procedure Overview
Venipuncture is a complex procedure. In order to perform venipuncture properly, phlebotomists need to be well-trained and skilled. Analyzed below are the essential steps required for a successful blood draw.
Step 1: Patient Identification
The phlebotomist greets, introduces himself to the patient and indicates the procedure to follow. Next, the phlebotomist identifies the patient and confirms his information by checking his / her armband or bracelet. Asking the patient for more information and cross referencing answers with the requisition form can further help the identification process. No blood must be drawn prior to completing the identification process. The same applies to the case of a missing armband or bracelet.
The phlebotomist is also responsible for assessing the patient’s physical status. That includes the patient’s stress levels, diet and exercise.
If there are doubts or matters to be further investigated regarding the process of patient identification, consulting with the site’s supervisor or a pathologist is mandatory.
Communication skills are priceless during both identification and the venipuncture procedure. Starting a conversation with the patient can take his mind of the procedure itself and relax him. A phlebotomist must familiarize himself with the Patient’s Bill of Rights as declared by the Joint Commission on Accreditation of Healthcare Organizations
Step 2: Requisition Form Check
The phlebotomist checks the requisition form for patient information, requested tests and any special requirements. Requisition forms must accompany drawn samples to the laboratory and are mandatory in order to process the specimen. Here’s a sample requisition form:
Step 3: Site and Vein Selection
At this stage, the phlebotomist selects a suitable site for the venipuncture procedure. The most frequent veins selected for venipuncture are the large, full median cubital and cephalic veins of the arm. However, the basilic vein on the dorsum of the arm is also used by phlebotomists. The dorsal hand veins are also acceptable.
In the unfortunate case the above sites can’t be used, foot veins are a phlebotomist’s last resort. It should be noted that foot veins are prone to complications and they should only be used for blood draw if everything else fails.
Sites suffering from hematoma, scars from burns and/or surgery should be avoided.
Check out the rest of the guide here.