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WHO Best Practices for Injections and Related Procedures Toolkit. Geneva: World Health Organization; 2010 Mar.
Phlebotomy is one of the most common invasive procedures in health care. This chapter outlines the risks associated with unsafe phlebotomy, and summarizes best practice in phlebotomy, with the aim of improving outcomes for health workers and patients. Institutions can use the principles given here to establish standing operating procedures (SOPs).
Unsafe phlebotomy can cause adverse effects for patients; such effects are rare, but range from pain or bruising at the site of puncture, to fainting, nerve damage and haematoma. The adverse events that have been best documented are in blood transfusion services, where poor venepuncture practice or anatomical abnormality has resulted in haematoma and injury to anatomical structures in the vicinity of the needle entry (35).
Another issue for patients is that if a blood sample is poorly collected or destroyed during transportation, the results may be inaccurate and misleading to the clinician, or the patient may have to undergo the inconvenience of repeat testing (36).
Poor infection-control practices can lead to bacterial infection at the site where the needle was inserted into the skin (37).
Both patients and health workers can be exposed through phlebotomy to blood from other people, putting them at risk from bloodborne pathogens. These pathogens include (2, 5, 12, 14, 17, 23, 31):
viruses, such as HBV, HCV and HIV; bacteria, such as syphilis; parasites, such as malaria.An example of the spread of bloodborne pathogens through phlebotomy is the reporting of outbreaks of hepatitis B associated with the use of glucometers (devices used to determine blood glucose concentration) (38, 39).
Another issue for health workers is sharps injuries; these commonly occur between the use and disposal of a needle or similar device.
Using best practices in phlebotomy reduces the risks to both patients and health workers. For example, the use of sharps protection devices and immediate disposal of the used syringe and needle as a single unit into a puncture-resistant sharps container (i.e. a safety container), markedly reduce needle-stick injuries and blood exposure among health workers (40).
In home-based care, phlebotomy can be made safer by improving sharps disposal, to minimize the risk of exposure to hollow-bore and venepuncture needles (41).
This section provides background information on phlebotomy, Sections 3.2.1–3.2.3 cover blood sampling, and Section 3.2.4 covers blood collection for transfusions.
Best practices in phlebotomy involve the following factors:
planning ahead – this is the most important part of carrying out any procedure, and is usually done at the start of a phlebotomy session;
using an appropriate location – the phlebotomist should work in a quiet, clean, well-lit area, whether working with outpatients or inpatients (see Section 3.3.1);
quality control – this is an essential part of best practice in infection prevention and control; in phlebotomy, it helps to minimize the chance of a mishap;
standards for quality care for patients and health workers – discussed in detail in Section 3.2.1.Table 3.1 lists the main components of quality assurance and explains why they are important.
Elements of quality assurance in phlebotomy.
Several factors can improve safety standards and quality of care for both patients and health workers, and laboratory tests. These factors include:
availability of appropriate supplies and protective equipment; availability of PEP; avoidance of contaminated phlebotomy equipment; appropriate training in phlebotomy; cooperation on the part of patients.Factors that influence the outcome of laboratory results during collection and transportation include:
knowledge of staff involved in blood collection; use of the correct gauge of hypodermic needle to prevent haemolysis or abnormal results; the appropriate anatomical insertion site for venepuncture; the use of recommended laboratory collection tubes; patient-sample matching (i.e. labelling); transportation conditions; interpretation of results for clinical management.Each of these issues is discussed in detail in WHO guidelines on drawing blood: best practices in phlebotomy (44).
Several choices of blood-sampling system are available for phlebotomy.
Closed systems – A hypodermic needle and syringe or a vacuum-extraction tube system are the closed systems most commonly used in blood sampling.
Open systems – Open systems include a hypodermic needle and syringe, and a winged steel needle attached to a syringe.
The system most appropriate for the procedure should be chosen. Closed systems are safer than open systems (45, 46). Table 3.2 gives details of existing systems, and outlines the advantages and disadvantages of each device.
Systems used for blood sampling.
It is best to choose the gauge of hypodermic needle that fits comfortably into the most prominent vein with little discomfort. Table 3.3 summarizes advice on appropriate gauge, length and device.
Recommended needle gauge, length and device for routine injection and phlebotomy procedures for different age groups.
If the needle is too large for the vein for which it is intended, it will tear the vein and cause bleeding (haematoma); if the needle is too small, it will damage the blood cells during sampling, and laboratory tests that require whole blood cells, or haemoglobin and free plasma, will be invalid.
Blood collection for transfusion requires a larger gauge than is used for blood drawing.
Collection of large volumes of blood is an everyday practice in blood transfusion services. The donated blood is tested, and processed to ensure that it is free from major infections that are transmissible by transfusion, therefore ensuring that it will not harm the recipient of the blood.
WHO has developed a set of basic requirements for blood transfusion services, which cover the steps to be undertaken before donation (47). Blood donation should be voluntary; it should not involve duress, coercion or remuneration. Also, potential blood donors should be selected carefully, according to the national criteria for donor selection.
Before a person donates blood (48):
the potential donor should be given pre-donation information, advice and counselling about the process of blood donation;
a relevant history of the donor should be taken, covering health and high-risk behaviour, and including:
a preliminary physical check-up of the donor should be undertaken, including weight, blood pressure, signs of infection or scarring at potential sites;
the donor should be offered fluids, to help reduce the risk of fainting after blood donation (51); the person should provide informed written consent, based on the national requirements.The relevant guidance given on planning, location and infection prevention and control practices should be followed, as should the guidance on closed systems. Additional requirements for a collection system for blood donation are given below.
This section provides practical guidance – Sections 3.3.1–3.3.3 cover blood sampling, and Sections 3.3.4–3.3.6 cover blood donation.
In the blood-sampling room for an outpatient department or clinic, provide a comfortable reclining couch with an arm rest.
In inpatient areas and wards:Ensure that the indications for blood sampling are clearly defined, either in a written protocol or in documented instructions (e.g. in a laboratory form) (36, 53).
At all times, follow the strategies for infection prevention and control listed in Table 2.4, in Section 2.1.5.
Collect all the equipment needed for the procedure and place it within safe and easy reach on a tray or trolley, ensuring that all the items are clearly visible. The equipment required includes:
a supply of laboratory sample tubes, which should be stored dry and upright in a rack; blood can be collected in
a sterile glass or bleeding pack (collapsible) if large quantities of blood are to be collected; well-fitting, non-sterile gloves;an assortment of blood-sampling devices (safety-engineered devices or needles and syringes, see below), of different sizes;
a tourniquet; alcohol hand rub; 70% alcohol swabs for skin disinfection; gauze or cotton-wool ball to be applied over the puncture site; laboratory specimen labels; writing equipment; laboratory forms; leak-proof transportation bags and containers; a puncture-resistant sharps container.Ensure that the rack containing the sample tubes is close, but away from the patient, to avoid it being accidentally tipped over.
Where the patient is adult and conscious, follow the steps outlined below.
Introduce yourself to the patient, and ask the patient to state their full name.Check that the laboratory form matches the patient's identity (i.e. match the patient's details with the laboratory form, to ensure accurate identification).
Ask whether the patent has allergies, phobias or has ever fainted during previous injections or blood draws.
If the patient is anxious or afraid, reassure the person and ask what would make them more comfortable.
Make the patient comfortable in a supine position (if possible). Place a clean paper or towel under the patient's arm.Discuss the test to be performed and obtain verbal consent, as shown in Annex F of WHO guidelines on drawing blood: best practices in phlebotomy (44). The patient has a right to refuse a test at any time before the blood sampling, so it is important to ensure that the patient has understood the procedure.
Illustrations to accompany these guidelines are given in Figure 3.1 in Section 3.4, at the end of this chapter.
Locate a vein of good size that is visible, straight and clear. The diagram in Section 3.4 shows common positions of the vessels, but many variations are possible. The median cubital vein lies between muscles and is usually the most easy to puncture. Under the basilic vein runs an artery and a nerve, so puncturing here runs the risk of damaging the nerve or artery and is usually more painful. DO NOT insert the needle where veins are diverting, because this increases the chance of a haematoma.
The vein should be visible without applying the tourniquet. Locating the vein will help in determining the correct size of needle.
Apply the tourniquet about 4–5 finger widths above the venepuncture site and re-examine the vein.In hospitalized patients, do not take blood from an existing peripheral venous access site because this may give false results. Haemolysis, contamination and presence of intravenous fluid and medication can all alter the results (54). Nursing staff and physicians may access central venous lines for specimens following protocols. However, specimens from central lines carry a risk of contamination or erroneous laboratory test results.
It is acceptable, but not ideal, to draw blood specimens when first introducing an in-dwelling venous device, before connecting the cannula to the intravenous fluids.
Unless drawing blood cultures, or prepping for blood collection, clean the site with a 70% alcohol swab and allow to dry (27–29, 36).
Note: alcohol is preferable to povidone iodine, because blood contaminated with povidone iodine may falsely increase levels of potassium, phosphorus or uric acid in laboratory test results (55, 56).
Apply firm but gentle pressure. Start from the centre of the venepuncture site and work downward and outwards to cover an area of 2 cm or more for 30 seconds.
Allow the area to dry for at least 30 seconds. Failure to allow enough contact time increases the risk of contamination.
DO NOT touch the cleaned site; in particular, DO NOT place a finger over the vein to guide the shaft of the exposed needle. It the site is touched, repeat the disinfection.
Perform venepuncture as follows.
Anchor the vein by holding the patient's arm and placing a thumb BELOW the venepuncture site. Ask the patient to form a fist so the veins are more prominent.Enter the vein swiftly at a 30 degree angle or less, and continue to introduce the needle along the vein at the easiest angle of entry.
Once sufficient blood has been collected, release the tourniquet BEFORE withdrawing the needle. Some guidelines suggest removing the tourniquet as soon as blood flow is established, and always before it has been in place for two minutes or more.
Withdraw the needle gently and apply gentle pressure to the site with a clean gauze or dry cotton-wool ball. Ask the patient to hold the gauze or cotton wool in place, with the arm extended and raised. Ask the patient NOT to bend the arm, because doing so causes a haematoma.
When obtaining multiple tubes of blood, use evacuated tubes, with a needle and tube holder. This system allows the tubes to be filled directly. If this system is not available, use a syringe or winged needle set instead.
If a syringe or winged needle set is used, best practice is to place the tube into a rack before filling the tube. To prevent needle-sticks, use one hand to fill the tube or use a needle shield between the needle and the hand holding the tube.
Pierce the stopper on the lab tube with the needle directly above the tube, using slow steady pressure. Do not press the syringe plunger because additional pressure increases the risk of haemolysis.
Where possible, keep the tubes in a rack and move the rack towards you. Inject downwards into the appropriate coloured stopper. DO NOT remove the stopper because it will release the vacuum.
If the sample tube does not have a rubber stopper, inject extremely slowly into the tube, to reduce the risk of haemolysis (to reduce the risk of haemolysis when transferring blood through a needle on a syringe, minimize the pressure and velocity used to transfer the specimen). DO NOT recap and remove the needle.
Before dispatch, invert the tubes containing additives for the required number of times (as specified by the local laboratory).
Draw blood collection tubes in the correct order, to avoid cross-contamination of additives between tubes. As colour coding and tube additives may vary, verify recommendations with local laboratories. Details of the recommended order are given in WHO guidelines on drawing blood: best practices in phlebotomy (44).
Discard the used needle and syringe or blood-sampling device into a puncture-resistant sharps container.
Check the label and forms for accuracy. The label should be clearly written with the information required by the laboratory, which is typically the patient's first and last name, file number, date of birth, and the date and time when the blood was taken.
Discard used items into the appropriate category of waste. Items used for phlebotomy that would not release a drop of blood if squeezed (e.g. gloves) may be discarded in the general waste, unless local regulations state otherwise.
Perform hand hygiene again, as described in step 4. Recheck the labels on the tubes and the forms before dispatch. Inform the patient when the procedure is over.Ask the patient or donor how they are feeling; check the insertion site to verify that it is not bleeding, then thank the patient and say something reassuring and encouraging before the person leaves.
Pack laboratory samples safely in a plastic leak-proof bag with an outside compartment for the laboratory request form. Place the requisition on the outside to help avoid contamination.
If there are multiple tubes, place them in a rack or padded holder to avoid breakage during transportation.
If blood spillage has occurred (e.g. because of a laboratory sample breaking in the phlebotomy area or during transportation, or excessive bleeding during the procedure), clean it up. An example of a safe procedure is given below.
Put on gloves and a gown or apron if contamination or bleaching of a uniform is likely in a large spill.
Mop up liquid from large spills using paper towels, and place them into the infectious waste. Remove as much blood as possible with wet cloths before disinfecting. Assess the surface to see whether it will be damaged by a bleach and water solution.For cement, metal and other surfaces that can tolerate a stronger bleach solution, food the area with an approximately 5000 parts per million (ppm) solution of sodium hypochlorite (1:10 dilution of a 5.25% chlorine bleach to water). This is the preferred concentration for large spills. Leave the area wet for 10 minutes.
For surfaces that may be corroded or discoloured by a strong bleach solution, clean carefully to remove all visible stains. Make a weaker solution and leave it in contact for more than 10 minutes. For example, an approximately 525 ppm solution (1:100 dilution of 5.25% bleach) is effective.
Prepare bleach solution fresh daily and keep it in a closed container because it degrades over time and in contact with the sun.
If a person was exposed to blood through nonintact skin, mucous membranes or a puncture wound, complete an incident report (see Section 4.3 for details of how to manage exposures to infectious materials). For transportation of blood samples outside a hospital, equip the transportation vehicle with a blood spillage kit (for details, see WHO guidelines on drawing blood: best practices in phlebotomy (44).
For collection of blood for donation, use the procedure detailed above for blood sampling (e.g. for hand hygiene and glove use), as far as it is relevant, and follow the six steps given below.
Select a large, firm vein, preferably in the antecubital fossa, from an area free from skin lesions or scars.
Apply a tourniquet or blood pressure cuff inflated to 40-60 mm Hg, to make the vein more prominent. Ask the donor to open and close the hand a few times.Once the vein is selected, release the pressure device or tourniquet before the skin site is prepared.
If the site selected for venepuncture is visibly dirty, wash the area with soap and water, and then wipe it dry with single-use towels.
One-step procedure (recommended – takes about one minute):Two-step procedure — (if chlorhexidine gluconate in 70% isopropyl alcohol disinfectant is not available, use the following procedure – takes about two minutes):
Whichever procedure is used, DO NOT touch the venepuncture site once the skin has been disinfected.Perform venepuncture using a smooth, clean entry with the needle, as described in step 6 of Section 3.3.3. Take into account the points given below, which are specific to blood donation.
In general, use a 16-gauge needle (see Table 3.3), which is usually attached to the blood collection bag; use of a retractable needle or safety needle with a needle cover is preferred if available).
Ask the donor to open and close the fist slowly every 10-12 seconds during collection. Remove the tourniquet when the blood flow is established or after 2 minutes, whichever comes first.About every 30 seconds during the donation, mix the collected blood gently with the anticoagulant, either manually or by continuous mechanical mixing.
Once the blood has been collected:
Ask the donor to remain in the chair and relax for a few minutes.Inspect the venepuncture site; if it is not bleeding, apply a bandage to the site; if it is bleeding, apply further pressure.
Ask the donor to sit up slowly and ask how the person is feeling.Before the donor leaves the donation room, ensure that the person can stand up without dizziness and without a drop in blood pressure.
Offer the donor some refreshments.Transfer the blood unit to a proper storage container according to the blood centre requirements and the product (57–59).
Ensure that collected blood samples are stored and delivered to the laboratory with completed documentation, at the recommended temperature and in a leak-proof, closed container (57, 59, 60).
Be aware of possible adverse events, and the actions to take if these occur. The document WHO guidelines on drawing blood: best practices in phlebotomy (44) provides details of possible adverse reactions and their prevention. The most frequent adverse events include haematoma,a vasovagal reaction or faint, and a delayed faint.
