PMLS 2 LAB MIDTERMS

• Phlebotomy


  The process of making an incision in a vein with a needle to draw blood for testing, transfusion, or research purposes
• Needlestick injuries


  Injuries caused by needles which can transmit infectious diseases
• 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
• Phlebotomy also poses risks for health workers
• 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
• 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
• 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
• Best practices in phlebotomy protect health workers as well as patients
• Institutions should conduct surveillance on sharps injuries and accidental exposure to blood, so that preventable factors can be identified
• 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
• Based on expert opinion, including considerations of convenience and cost, these guidelines recommend a one-step procedure for skin preparation
• The Cochrane group found that no research had been conducted to compare "alcohol alone" or "any skin disinfectant followed by alcohol for skin preparation" in reducing the risk of blood contamination or bacteraemia
• Until better evidence emerges, decisions would probably need to be based on convenience and cost
• Skin preparation procedure


  1. Clean the skin with a combination of 2% chlorhexidine gluconate in 70% isopropyl alcohol

  2. Cover the whole area

  3. Ensure the skin area is in contact with the disinfectant for at least 30 seconds

  4. Allow the area to dry completely (about 30 seconds)
• 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 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
• Phlebotomy - the drawing of blood - has been practiced for centuries and is still one of the most common invasive procedures in health care
• Practice varies considerably between countries, and between institutions and individuals within the same country
• 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
• Phlebotomy has the potential to expose health workers and patients to blood from other people, putting them at risk from bloodborne pathogens
• Outbreaks of hepatitis B have been reported with the use of glucometers (devices used to determine blood glucose concentration)
• Diseases such as malaria and syphilis may also be transmitted via contaminated blood
• 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
• Factors that increase the risk of haemolysis

  • 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
• Nerve injury and damage to adjacent anatomical structures occurred infrequently, and syncope occurred in less than 1% of individuals
• 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
• Injuries from sharps commonly occur between the use and disposal of a needle or similar device
• One way to reduce accidental injury and blood exposure among health workers is to replace devices with safety (i.e. engineered) devices
• Safety devices can avoid up to 75% of percutaneous injuries
• If safety devices 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
• 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
• Home-based care is a growing component of health delivery, and current global trends suggest that home-based phlebotomy will become increasingly common
• In home-based care, stronger protection of community-based health workers and the community will be needed, which 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 and lancets