Phlebotomy – the drawing of blood – has been practised for centuries and is still one of the most common invasive procedures in health care. Each step in the process of phlebotomy affects the quality of the specimen and is thus important for preventing laboratory error, patient injury and even death. For example, the touch of a finger to verify the location of a vein before insertion of the needle increases the chance that a specimen will be contaminated. This can cause false blood culture results, prolong hospitalization, delay diagnosis and cause unnecessary use of antibiotics. Jostling and jarring of test tubes in transit can lyse or break open red blood cells, causing false laboratory results. Clerical errors in completing forms and identifying patients are common, costly and preventable. Other adverse effects for patients are common; they include bruising at the site of puncture, fainting, nerve damage and haematomas. These guidelines outline the simple but important steps that can make phlebotomy safer for patients.
Phlebotomy also poses risks for health workers. It is still common to see a phlebotomist carry out dangerous practices known to increase the risk of needle-stick injury and transmission of disease. Dangerous practices include:
recapping used needles using two hands;
recapping and disassembling vacuum-containing tubes and holders;
reusing tourniquets and vacuum-tube holders that may be contaminated with bacteria and sometimes blood;
working alone with confused or disoriented patients who may move unexpectedly, contributing to needle-sticks.
Phlebotomy involves the use of large, hollow needles that have been in a blood vessel. The needles can carry a large volume of blood that, in the event of an accidental puncture, may be more likely to transmit disease than other sharps. Bloodborne organisms that have been transmitted after needle-sticks include viruses such as hepatitis B and human immunodeficiency virus (HIV), bacteria such as syphilis and parasites such as malaria.
Producing the guidelines
These guidelines were produced to improve the quality of blood specimens and the safety of phlebotomy for health workers and patients, by promoting best practices in phlebotomy.
In April 2008, the WHO Injection Safety programme – part of the Department of Essential Health Technologies (EHT) at WHO Headquarters in Geneva – convened a consultation on best practices for phlebotomy and blood collection. The consultation included special categories, such as arterial blood sampling, capillary blood sampling and paediatric blood collection. A working group of international experts and colleagues from WHO departments identified the need for phlebotomy guidelines, and this document was produced in response.
This document provides guidance on the steps recommended for safe phlebotomy, and reiterates the accepted principles for drawing and collecting blood. The guidelines are based on a literature review that focused on identifying systematic literature reviews and evidence relating specifically to phlebotomy practices in developing countries. Draft guidelines and evidence were reviewed by an expert panel, who reached consensus on the recommendations.
Protecting patents
To reduce the risk of adverse effects for patients, health workers undertaking phlebotomy need to be trained in procedures specific to the types of specimen they collect. Such procedures may include arterial sampling, capillary sampling, blood culture collection and venous blood draws. Health workers who collect specimens from children and infants will need special training and practice for these procedures. Phlebotomists working in settings with more technology may be trained in techniques for plasma and red cell exchange, photophoresis, stem cell collection and cord blood collection. Health workers may need to collect specimens from in-dwelling central lines or arterial lines. Training should include techniques that ensure that the specimen collected will be adequate, and measures that reduce the risk of contamination, clerical error, infection and injury.
When taking blood, health workers should wear well-fitting, non-sterile gloves, and should also carry out hand hygiene before and after each patient procedure, before putting on gloves and after removing them. The blood should be taken in a dedicated location that ensures patient comfort and privacy. To remove the risk of environmental contamination with pathogens, counter and work surfaces, and chair arms should be cleaned with disinfectant at the start of each shift and when visibly dirty. To prevent infections and other adverse events, health workers should follow the guidelines on patient identification, hand hygiene, use of gloves, skin disinfection, use of appropriate blood-sampling devices and safe transportation of laboratory samples.
Patient consent and cooperation are important components of respecting patient rights. A patient information leaflet or poster that explains the procedure in simple terms is helpful.
Protecting health workers
Best practices in phlebotomy protect health workers as well as patients. One way to reduce accidental injury and blood exposure among health workers is to use safety (i.e. engineered) devices such as retractable lancets, syringes with needle covers or retractable needles and, when appropriate, plastic laboratory tubes. Another approach is to eliminate two-handed needle recapping and manual device disassembly, and instead dispose of the sharps into a puncture-resistant sharps container (i.e. a safety container) immediately after use. The best practice is to discard the needle and syringe, or needle and tube holder, as a single unit, into a sharps container that is clearly visible and within arm's reach. The size of the container should permit disposal of the entire device rather than just the needle.
Institutions should conduct surveillance on sharps injuries and accidental exposure to blood, so that preventable factors can be identified. Support services should also be available for health workers accidentally exposed to blood. These should include immunization with hepatitis B before assuming duties that include potential exposure to blood and body fluids, and post-exposure prophylaxis for HIV and hepatitis B. All health-care facilities should display clear instructions for procedures to follow in case of accidental exposure to blood and body fluids.
These guidelines also outline the responsibilities of managerial staff, including provision of:
gloves in multiple sizes, single-use disposable needles, and syringes or lancing devices in sufficient numbers to ensure that each patient has a sterile needle and collection device or equivalent for each blood sampling;
sufficient laboratory sample tubes to prevent reuse and manual washing.
Best practice in disinfection
After reviewing the evidence on best practice in phlebotomy, the expert panel found that further evidence was needed on the best method for skin preparation before blood collection for the purpose of blood transfusion. The panel commissioned a systematic review from the Cochrane group to investigate the literature on whether “alcohol alone” or “any skin disinfectant followed by alcohol for skin preparation” is more effective in reducing the risk of blood contamination or bacteraemia.
The Cochrane group found that no research had been conducted to compare these two methods, and commented that, until better evidences emerges, decisions would probably need to be based on convenience and cost.
In line with WHO guidelines for the development of recommendations, additional infection control experts were consulted. Based on expert opinion, including considerations of convenience and cost, these guidelines recommend a one-step procedure for skin preparation. Health workers should clean the skin with a combination of 2% chlorhexidine gluconate in 70% isopropyl alcohol, covering the whole area and ensuring that the skin area is in contact with the disinfectant for at least 30 seconds; they should then should allow the area to dry completely (about 30 seconds).
Implementing and revising the guidelines
In some countries, these guidelines will be adapted to meet local needs, although key steps and recommendations will be maintained. The WHO Injection Safety programme can also provide technical support for adapting and implementing the guidelines at regional and country levels, if requested. The feasibility of recommended practices and the impact of the guideline on phlebotomy practices will be evaluated by the WHO Injection Safety programme, in collaboration with WHO Regional Offices. The recommendations in this document are expected to remain valid until 2014, when they will be reviewed.
