Laboratory requisitions will frequently note the time a blood sample should be drawn?
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). Show
3.1. Potential effects of unsafe phlebotomyUnsafe 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):
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. 3.2. Background information on best practices in phlebotomyUsing 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:
Table 3.1 lists the main components of quality assurance and explains why they are important. Table 3.1Elements of quality assurance in phlebotomy. 3.2.1. Quality care for patients and health workersSeveral factors can improve safety standards and quality of care for both patients and health workers, and laboratory tests. These factors include:
3.2.2. Quality of laboratory samplingFactors that influence the outcome of laboratory results during collection and transportation include:
Each of these issues is discussed in detail in WHO guidelines on drawing blood: best practices in phlebotomy (44). 3.2.3. Blood-sampling systemsSeveral choices of blood-sampling system are available for phlebotomy.
Choice of systemThe 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. Choice of gaugeIt 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. Table 3.3Recommended 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. 3.2.4. Blood collection for blood transfusion purposesCollection 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. Before a blood donationWHO 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):
Collection systems – minimum requirementsThe 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.
3.3. Practical guidance on best practices in phlebotomyThis 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. 3.3.1. Provision of an appropriate location
3.3.2. Provision of clear instructionsEnsure 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). 3.3.3. Procedure for drawing bloodAt all times, follow the strategies for infection prevention and control listed in Table 2.4, in Section 2.1.5. Step 1. Assemble equipmentCollect 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:
Ensure that the rack containing the sample tubes is close, but away from the patient, to avoid it being accidentally tipped over. Step 2. Identify and prepare the patientWhere the patient is adult and conscious, follow the steps outlined below.
Step 3. Select the siteIllustrations to accompany these guidelines are given in Figure 3.1 in Section 3.4, at the end of this chapter. General
Hospitalized patientsIn 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. Step 4. Perform hand hygiene and put on gloves
Step 5. Disinfect the entry site
Step 6. Take bloodVenepuncturePerform venepuncture as follows.
Step 7. Fill the laboratory sample tubes
See Figure 3.2 in Section 3.4. Step 8. Draw samples in the correct orderDraw 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). Step 9. Clean contaminated surfaces and complete patient procedure
Step 10. Prepare samples for transportation
Step 11. Clean up spills of blood or body fluidsIf 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.
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). 3.3.4. Collecting blood for blood donationFor 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. Step 1. Identify donor and label blood collection bag and test tubes
Step 2. Select the vein
Step 3. Disinfect the skin
Step 4. Perform the venepuncturePerform 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.
Step 5. Monitor the donor and the donated unit
Step 6. Remove the needle and collect samples
3.3.5. After a blood donationDonor careOnce the blood has been collected:
Blood unit and samples
3.3.6. Adverse events in blood donationBe 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. 3.4. Illustrations for best practices in phlebotomyFigure 3.2Filling tubesWhat is a requisition in phlebotomy?A lab requisition form is used by healthcare professionals to request laboratory tests such as urine or blood testing. They are also called test requisition forms. When blood, urine, or tissue is sent to a lab from a doctor's office a lab requisition form is required.
Why it is best to time some blood tests while the client is in a basal state?The basal state (the early morning approximately 12 hours after the last ingestion of food) is recommended for determining the concentration of body constituents such as glucose, cholesterol, triglycerides, electrolytes, and proteins.
What precautions should be taken when giving blood sample?Blood Specimens - Safety
Wear personal protective equipment such as safety glasses, gloves, laboratory coats. If you have cuts or abrasions on the skin of your hands, cover them with adhesive dressing. Use needles and lancets only once, and dispose of them in a “sharps” container for decontamination.
How many more times should a phlebotomist try to perform a venipuncture?Do not attempt a venipuncture more than twice. Notify your supervisor or patient's physician if unsuccessful. 5. Select the appropriate vein for venipuncture.
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