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WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy. Geneva: World Health Organization; 2010.

Cover of WHO Guidelines on Drawing Blood

WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy.

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1Introduction

1.1. Overview

Phlebotomy – the drawing of blood – has been practiced for centuries and is still one of the most common invasive procedures in health care (1). However, practice varies considerably between countries, and between institutions and individuals within the same country (2). These differences include variations in blood-sampling technique, training (both formal and “on-the-job”), use of safety devices, disposal methods, reuse of devices and availability of hepatitis B vaccine.

The methods and the evidence base used to develop this document are given in Annex A.

1.1.1. Issues in phlebotomy

By its nature, phlebotomy has the potential to expose health workers and patients to blood from other people, putting them at risk from bloodborne pathogens. These pathogens include human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and those causing viral haemorrhagic fevers (Crimean Congo haemorrhagic fever, Ebola, Lassa and Marburg) and dengue (3). For example, outbreaks of hepatitis B have been reported with the use of glucometers (devices used to determine blood glucose concentration) (4, 5). Diseases such as malaria and syphilis may also be transmitted via contaminated blood (6, 7), and poor infection-control practices may lead to bacterial infection where the needle is inserted and contamination of specimens.

If a blood sample is poorly collected, the results may be inaccurate and misleading to the clinician, and the patient may have to undergo the inconvenience of repeat testing. The three major issues resulting from errors in collection are haemolysis, contamination and inaccurate labelling.

Factors that increase the risk of haemolysis include:

  • use of a needle of too small a gauge (23 or under), or too large a gauge for the vessel;
  • pressing the syringe plunger to force the blood into a tube, thus increasing the shear force on the red blood cells;
  • drawing blood specimens from an intravenous or central line;
  • underfilling a tube so that the ratio of anticoagulant to blood is greater than 1:9;
  • reusing tubes that have been refilled by hand with inappropriate amounts of anticoagulants;
  • mixing a tube too vigorously;
  • failing to let alcohol or disinfectant dry;
  • using too great a vacuum; for example, using too large a tube for a paediatric patient, or using too large a syringe (10–20 ml).

Serious adverse events linked with phlebotomy are rare, but may include loss of consciousness with tonic clonic seizures. Less severe events include pain at the site of venepuncture, anxiety and fainting. The best documented adverse events are in blood transfusion services, where poor venepuncture practice or anatomical abnormality has resulted in bruising, haematoma and injury to anatomical structures in the vicinity of the needle entry. For example, one study reported bruising and haematoma at the venepuncture site in 12.3% of blood donors (8). Nerve injury and damage to adjacent anatomical structures occurred infrequently, and syncope occurred in less than 1% of individuals (8). Vasovagal attacks occurred occasionally, varying from mild to severe; fainting was reported in 5.3% of cases and usually occurred in first-time female blood donors (8-11).

Injuries from sharps (i.e. items such as needles that have corners, edges or projections capable of cutting or piercing the skin) commonly occur between the use and disposal of a needle or similar device (12, 13). One way to reduce accidental injury and blood exposure among health workers is to replace devices with safety (i.e. engineered) devices (1416). Safety devices can avoid up to 75% of percutaneous injuries (17); however, if they are disassembled or manually recapped, or if the needle safety feature is not activated, exposure to blood becomes more likely. Eliminating needle recapping and instead immediately disposing of the sharp into a puncture-resistant sharps container (i.e. a safety container) markedly reduces needle-stick injuries (18, 19).

Reporting of accidental exposure to blood and body fluids is more frequent from well-established health-care systems; however, it is thought that the incidence of such exposures is actually higher in systems that are not so well equipped (20, 21).

Home-based care is a growing component of health delivery, and current global trends suggest that home-based phlebotomy will become increasingly common. In this situation, stronger protection of community-based health workers and the community will be needed. This can be achieved by improving sharps disposal, and by using safety needles with needle covers or retractable needles to minimize the risk of exposure to needles (22) and lancets.

1.1.2. The need for guidelines

Phlebotomy services are available worldwide in a range of health-care facilities (e.g. hospitals, outpatient facilities and clinics), and are usually performed by both medical and nonmedical personnel. Laboratory staff or members of phlebotomy teams appear to achieve lower rates of contamination than staff who have broader responsibilities, even if both have the same training (23). For example, for obtaining a blood sample for routine genetic screening of babies, the use of capillary heel-pricks by a trained phlebotomist was found to be the most successful and pain-free blood-sampling procedure (capillary sampling is undertaken for rapid tests that require small quantities of blood) (24).

Phlebotomy practice varies among health-care personnel, even though perceptions of risk are similar and there are guidelines for such practice (20, 25). To help standardize practice, several countries have established formal training that phlebotomists must undertake before they can practice clinically, but physicians can often practice phlebotomy without formal training (26).

During phlebotomy procedures, the greatest concern is the safety of health workers and patients; therefore, guidance for staff on best practice is critical (27, 28). Training on, and adherence to, the guidance presented here should substantially reduce the risks to both patients and staff, and will improve blood collection for laboratory tests and from blood donors.

1.1.3. Definitions

For the purposes of this document, the term “phlebotomy” covers the terms:

  • blood sampling for purposes of laboratory tests;
  • blood collection for donation.

1.2. Purpose and scope

The aim of these guidelines is to summarize best practices in phlebotomy, to improve outcomes for health workers and patients.

These guidelines recommend best practices for all levels of health care where phlebotomy is practised. They extend the scope of the existing guidelines from the World Health Organization (WHO) and the Safe Injection Global Network (SIGN), which is a WHO-hosted network. These existing guidelines are:

  • WHO Aide-memoire for a national strategy for the safe and appropriate use of injection (29);
  • Best infection control practices for intradermal, subcutaneous, and intramuscular needle injections (30).

This document also discusses best practices for venous and arterial blood sampling, and blood collection for transfusion for adult and paediatric populations. The document does not discuss collection from in-dwelling central lines, arterial lines or cord blood; also, it does not cover stem cell collection.

1.3. Objectives

The objectives of these guidelines are to:

  • improve knowledge and awareness of the risks associated with phlebotomy among all health workers involved in the practice;
  • increase safe practices and reduce bloodborne virus exposure and transmission;
  • improve patient confidence and comfort;
  • improve the quality of laboratory tests.

1.4. Target audience

This document is aimed at:

  • people who perform or supervise phlebotomy in the private and public sectors, in hospitals, community clinics and other health-care facilities, including those involved in home-based care;
  • health trainers and educators;
  • procurement officials (who need to be aware of which equipment and supplies are safe and cost effective).

1.5. Indications for blood sampling and blood collection

The most common use of blood sampling is for laboratory tests for clinical management and health assessment. Categories that require specialist training include:

  • arterial blood gases for patients on mechanical ventilation, to monitor blood oxygenation;
  • neonatal and paediatric blood sampling

    heel-prick (i.e. capillary sampling);

    scalp veins in paediatrics;

  • capillary sampling (i.e. finger or heel-pricks or, rarely, an ear lobe puncture) for analysis of capillary blood specimens for all ages; examples include testing of iron levels before blood donation, blood glucose monitoring, and rapid tests for HIV, malaria and syphilis.

Blood collection is used to obtain blood from donors for various therapeutic purposes.

1.6. Structure of document

This document is divided into five parts:

  • Part I introduces the topic and the document.
  • Part II covers different aspects of phlebotomy. Each chapter in this part is divided into sections that give background information, practical guidance and illustrations (where applicable). Part 2 includes

    the steps recommended for safe phlebotomy, including accepted principles for drawing and collecting blood (Chapter 2);

    the various open and closed systems available for phlebotomy (Chapter 3);

    collection of blood for transfusion (Chapter 4);

    collection of arterial blood, for determination of blood gases (Chapter 5);

    aspects of blood sampling specific to paediatric and neonatal patients (Chapter 6);

    capillary sampling (Chapter 7)

  • Part III deals with implementation, monitoring and evaluation; it covers

    ways to implement best practices in phlebotomy (Chapter 8);

    use of a monitoring and evaluation system to document improvements in phlebotomy practice (Chapter 9).

  • Part IV lists the references.
  • Part V contains a set of annexes that provide additional information on specific topics; it also includes a glossary.
Copyright © 2010, World Health Organization.

All rights reserved. Publications of the World Health Organization can be obtained from WHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264; fax: +41 22 791 4857; e-mail: tni.ohw@sredrokoob). Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press, at the above address (fax: +41 22 791 4806; e-mail: tni.ohw@snoissimrep).

Bookshelf ID: NBK138675

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