From the Guidelines
Venipuncture is a medical procedure that involves puncturing a vein with a needle to collect a blood sample or administer intravenous therapy, and it requires proper technique and equipment to minimize complications and ensure patient safety. This procedure is commonly performed in healthcare settings and involves inserting a hollow needle into a visible vein, usually in the antecubital fossa (the inner bend of the elbow), though other sites like the back of the hand or wrist may be used when necessary 1. The use of a 21-gauge needle is preferred to minimize the risk of hemolysis, and the median cubital vein is considered the preferred site for blood withdrawal 1.
The procedure requires proper patient identification, appropriate equipment including needles, collection tubes, tourniquets, alcohol swabs, and adherence to infection control practices. Healthcare providers must follow a specific sequence: applying a tourniquet to make veins more prominent, cleaning the site with an antiseptic, inserting the needle at the proper angle (usually 15-30 degrees), collecting the required blood volume, removing the tourniquet, withdrawing the needle, and applying pressure to prevent bruising.
Some key considerations for venipuncture include the use of ultrasound-guided venepuncture, which has been shown to be associated with a lower incidence of complications and a higher rate of success than 'blind' venepuncture 1. Additionally, the position of the patient (standing, lying, sitting) can have an impact on the hematocrit, and thus may cause fluctuations in the levels of the analytes 1. The preparation of the blood collection sites necessitates an accurate cleaning of the skin with alcohol (2-propanol) that should be allowed to evaporate, given that the contamination of blood with residual alcohol may induce hemolysis, increase the concentrations of some analytes, and therefore produce interferences 1.
- Key steps in venipuncture include:
- Applying a tourniquet to make veins more prominent
- Cleaning the site with an antiseptic
- Inserting the needle at the proper angle (usually 15-30 degrees)
- Collecting the required blood volume
- Removing the tourniquet
- Withdrawing the needle
- Applying pressure to prevent bruising
- Important considerations for venipuncture include:
- Using a 21-gauge needle to minimize the risk of hemolysis
- Using the median cubital vein as the preferred site for blood withdrawal
- Using ultrasound-guided venepuncture to reduce complications and increase success rates
- Avoiding contamination of blood with residual alcohol to prevent interferences with laboratory assays.
From the Research
Definition of Venipuncture
- Venipuncture is a medical procedure that involves the insertion of a needle into a vein to collect blood samples or insert a venous access device 2.
- It is a common procedure used in various medical settings, including hospitals, clinics, and laboratories.
- Venipuncture is considered a relatively low-risk procedure, but it can be associated with bleeding, especially in patients with coagulopathy or those taking antithrombotic medications 2.
Related Concepts
- Anticoagulation therapy is often used to prevent and treat venous thromboembolism, and patients on this therapy may require special consideration when undergoing venipuncture [(3,4)].
- Topical coagulant agents and hemostatic materials can be used to control bleeding during and after venipuncture 5.
- Antiplatelet agents and anticoagulants are types of medications that can affect blood clotting and may be relevant to venipuncture procedures 6.