Longquiz

• Activity 2 objectives


  1. Discuss the importance of specimen aliquoting properly

  2. Demonstrate correct specimen labeling

  3. Operate the centrifuge correctly

  4. Aliquot blood specimen properly
• Infection


  A condition that results when a microorganism is able to invade the body, multiply, and cause injury or disease
• Chain of infection components

  • Infectious agent
  • Reservoir
  • Exit pathway
  • Mode of transmission
  • Entry pathway
  • Susceptible host
• Healthcare Associated Infections (HAI) apply to infections associated with healthcare delivery in any healthcare setting including home care
• Nosocomial infection is a HAI acquired in hospitals
• HAIs remain to be a major problem in the healthcare industry but are preventable by appropriate control measures in conjunction with Standard Precautions
• Proper hand washing, and correct donning and doffing of Personal Protective Equipment (PPE) are strategies to prevent HAIs
• Hand hygiene


  The first line of defense to reduce microbial transmission by performing proper hand hygiene
• Routine hand washing is a one-minute procedure that is generally considered to be the single most important method for preventing the spread of infection, provided that it is achieved properly
• CDC/HICPAC guidelines recommend the use of alcohol-based antiseptic hand cleaners when hand washing facility is not available
• World Health Organization (WHO) requires all healthcare professionals to practice the "5 Moments for Hand Hygiene"
• Personal Protective Equipment (PPE) acts as a barrier between infectious materials and the skin and mucous membranes when used properly
• Items that may be included in PPE

  • Gloves
  • Safety glasses
  • Proper footwear
  • Respirators
  • Lab gowns
• To minimize the spread of infection

  PPE must be properly worn (don), removed (doff) and disposed
• Specimen labeling


  Proper identification of the specimen must be maintained at each step of the testing process to help assure patient safety
• Centrifugation


  The centrifuge is commonly found in the clinical laboratory and a basic knowledge of the theory of centrifugation is more than useful
• Components of a centrifuge

  • Lid
  • Power switch
  • Brake
  • Tachometer
• Applications of centrifuges


  • Separation of serum or plasma from red blood cells
  • Separation of precipitated solids from the liquid phase of a mixture
  • Separation of liquids of varying density
• Centrifugation


  Technique designed to utilize centrifugal forces greater than the force of gravity to speed up the sedimentation rate of particles
• Centrifugal force depends on

  • Mass
  • Speed
  • Radius
• Particles suspended in a fluid move under the influence of gravity towards the bottom of a vessel at a rate depending on their size and density
• Relative Centrifugal Force (RCF)

  Force measured in multiples of the Earth's gravitational force, generated by a rotor's speed in revolutions per minute (rpm) and radius of rotation
• Equations for calculating RCF from known rpm and radius, and calculating rpm from known RCF and radius are shown in Table 1
• Aliquoting means to separate a portion of whole blood, serum, plasma, or any fluid and place it in a separate tube for various reasons
• Tourniquet application, vein selection, and site disinfection


  Proper procedure and demonstration of tourniquet application, vein selection, and site disinfection
• Tourniquet serves two functions in venipuncture: impeding venous blood flow for easier vein location and providing a larger blood amount for collection
• Tourniquet must be applied for a maximum of 1 minute and released for 2 minutes before re-application
• Preferred site for venipuncture is the antecubital fossa, with the median cubital vein being the vein of choice
• Veins for venipuncture


  • Median cubital
  • Cephalic
  • Basilic
• Median cubital vein


  • Vein of choice because it is large, not movable, closer to the surface of the skin, more isolated from underlying structures, and the least painful
• When median cubital vein is inaccessible


  Next vein of choice is the cephalic
• Cephalic vein


  • Located on the thumb side, difficult to locate, has more tendency to move
• Basilic vein


  • Last choice because it is the least firmly anchored, has a tendency to roll, and is near to the median nerve and brachial artery
• Palpation


  Locating veins by sight and touch using the index finger of the non-dominant hand through a pushing motion
• Veins


  Spongy and resilient tube-like structures, different from rigid tendons, do not pulsate like arteries
• Thumb must not be used to palpate because it has a pulse beat
• Degerming the site


  Using 70% isopropyl alcohol with friction in a back and forth movement, allowing the alcohol to air dry for 30-60 seconds for maximum bacteriostatic action
• Performing a venipuncture before the alcohol has dried causes a stinging sensation to the patient and can hemolyze the sample
• Wiping with cotton, gauze, or blowing the site causes re-introduction of microorganisms to the site
• Evacuated Tube System (ETS) of Venipuncture


  Collecting blood samples directly into the evacuated tube, eliminating the need to transfer samples and minimizing the risk of exposure to biohazards