WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy

Phlebotomy, the process of drawing blood for diagnostic or therapeutic purposes, is a vital clinical procedure performed worldwide. Ensuring safe, effective, and standardized blood collection is critical both for accurate laboratory testing and for protecting patients and healthcare workers from risks of infection and other complications. The World Health Organization (WHO) has published comprehensive guidelines that outline best practices in phlebotomy. This page summarizes those recommendations, focusing on infection prevention, patient safety, quality of specimen collection, and proper procedures.

Importance of Standardized Phlebotomy Practices

Standardization in blood collection helps ensure sample integrity and reliability of test results, which are essential for correct diagnosis and treatment. Incorrect procedures can lead to hemolysis, contamination, or insufficient sample volumes which compromise laboratory analysis. Furthermore, breaches in infection control may expose both patients and healthcare workers to blood-borne pathogens like HIV, hepatitis B, and hepatitis C.

WHOs guidelines emphasize the use of safe and aseptic techniques to minimize these risks while promoting patient comfort and reducing anxiety during procedures.

Pre-procedure Preparation

Patient Identification and Communication

Before drawing blood, it is essential to correctly identify the patient using at least two identifiers, such as full name and date of birth. This prevents sample mix-ups which can lead to diagnostic errors.

Healthcare workers should clearly explain the procedure to the patient, answering any questions they may have to ease anxiety and obtain informed consent. Understanding patient history for any bleeding disorders or allergies is important.

Hand Hygiene and Personal Protective Equipment (PPE)

Performing proper hand hygiene before and after the procedure is mandatory. WHO recommends washing hands with soap and water or using an alcohol-based hand rub.

Healthcare workers must wear appropriate PPE, including gloves and, if necessary, masks or eye protection especially if theres risk of blood splash. Gloves should be changed between patients.

Equipment and Materials

Use only sterile, single-use needles and blood collection devices. Gather all required materials before starting, including:

• Disposable gloves
• Sterile needles and syringes or vacuum tubes
• Alcohol swabs (70% isopropyl or ethyl alcohol)
• Tourniquet
• Sharps container
• Gauze, adhesive bandages
• Labels for sample tubes

Site Selection and Preparation

The preferred site for venipuncture is the median cubital vein, located in the antecubital fossa (inner elbow). If not feasible, alternatives include cephalic or basilic veins of the arm or dorsal hand veins.

Examine the site to find a suitable, palpable vein free from infection, scarring, or inflammation. Avoid areas with hematomas or edematous tissues.

Once the vein is identified, apply a tourniquet 710 cm above the puncture site to engorge the vein but not so tight as to cause arterial occlusion or discomfort. The tourniquet should not be left in place for more than one minute to prevent hemoconcentration.

Clean the puncture site thoroughly with a single-use 70% alcohol swab, moving in a circular motion from inside to outside. Allow the skin to air dry completely before needle insertion to maximize antiseptic effect and avoid hemolysis caused by alcohol contamination.

Blood Collection Procedure

Venipuncture Technique

Use an appropriate needle size based on patient age and vein size (commonly 21-23 gauge for adults). Hold the needle bevel facing upwards to minimize vein trauma.

Insert the needle smoothly at a 1530 degree angle with the skin, advancing until blood flow is observed in the hub. Collect the required volume in properly labeled tubes in the correct order of draw to prevent cross-contamination of additives between tubes. Common order: blood culture tubes, citrate tubes, serum tubes, heparin tubes, EDTA tubes, fluoride tubes.

Release the tourniquet as soon as blood flow is established. Never remove the needle while the tourniquet is still applied.

After Blood Collection

Withdraw the needle gently and immediately apply sterile gauze over the puncture site. Ask the patient to apply pressure to prevent hematoma formation. Once bleeding stops, secure with adhesive bandage.

Dispose of needles and other sharps promptly and safely into designated sharps containers to prevent needlestick injuries.

Label each tube at the bedside with patient identification information before leaving the patient to avoid sample misidentification. Record the procedure details, including time and phlebotomists name, in patient records.

Infection Prevention and Safety Considerations

WHO guidelines stress the importance of infection control throughout the procedure:

• Use single-use sterile equipment only.
• Wear gloves and practice hand hygiene before and after contact with blood.
• Activate safety-engineered devices where available.
• Never recap needles after use; dispose immediately.
• Clean and disinfect work surfaces regularly.
• Handle and transport specimens in leak-proof containers.

Proper training on phlebotomy protocols reduces errors and occupational exposure to bloodborne pathogens.

Considerations for Special Populations

Children and Infants: Venipuncture may require smaller needles (23-25 gauge) and may be more challenging due to smaller veins and patient anxiety. Using distraction techniques and involving caregivers can ease procedure.

Elderly Patients: Fragile veins require gentle technique, minimal tourniquet time, and careful handling to prevent hematoma or vein collapse.

Patients with Difficult Venous Access: Alternative methods such as capillary blood collection or using ultrasound guidance may be required.

Troubleshooting Common Problems

Failure to Obtain Blood Flow

If blood does not flow immediately:

• Check vein selection and needle positioning.
• Adjust needle angle slightly or withdraw and reinsert.
• Release and reapply tourniquet after a short pause if necessary.

Hematoma Formation

Usually caused by puncturing through the vein or inadequate pressure post-draw. Prevent by proper vein selection, steady needle insertion, and applying firm pressure after needle withdrawal.

Hemolysis of Sample

Avoid excessive force during aspiration, shaking tubes vigorously, or contamination with alcohol at the puncture site. This can cause misleading laboratory results.

Post-procedure Handling of Specimens

Specimens should be transported to the laboratory rapidly and at appropriate temperatures depending on the test. Avoid excessive shaking or agitation. Proper labeling and documentation are crucial for traceability and to maintain test validity.

Summary

Safe and effective phlebotomy depends on strict adherence to standardized procedures covering patient identification, hand hygiene, site selection, aseptic technique, and correct specimen handling. Protecting the patient and healthcare worker from infection remains paramount. WHO

The WHO guidelines on drawing blood emphasize that meticulous attention during every stage of phlebotomyfrom patient preparation to specimen transportenhances diagnostic accuracy and safety. Continuing education and competency assessments of phlebotomists help maintain high standards worldwide.