Principles of Medical Technology 2 (Laboratory)

• Hand contact is the most common way of transmitting infection
• Hand washing is the single most effective way to prevent the spread of infections
• Hand washing


  • Important safety precaution
  • Should be practiced after direct contact with patients and laboratory specimens
• Use of gloves is not a substitute for hand washing
• Accidental skin contact with blood, body fluids, or tissues should be immediately washed with soap and water
• When hands should be washed

  • Before eating, drinking, smoking, applying makeup
  • Changing contact lenses
  • Before and after using lavatory facilities
  • After the completion of work
  • Before leaving the laboratory
  • Before all other activities which entail hand contact with mucous membranes, eyes, and breaks in the skin
• Five steps to wash hands the right way

  1. Wet your hands with clean, running water (warm or cold), turn off the tap, and apply soap

  2. Lather hands by rubbing them together with the soap. Lather the backs of hands, between fingers, and under nails

  3. Scrub hands for at least 20 seconds

  4. Rinse hands well under clean, running water

  5. Dry hands using a clean towel or air dry them
• Gloves


  • Provide protective barriers against blood and other body fluids and from contamination of hands with microorganism
  • Designed to fit tightly to allow precision work
  • Must be worn when processing blood or body fluid specimens, when handling contaminated materials, during cleaning and decontamination procedures
• Gloves must be changed after contact with material that may contain a high concentration of microorganisms
• Gloves must be removed promptly after use and disposed of in biohazardous waste
• Gloves must never be reused
• If gloves are soiled or came into contact with potentially infectious specimens, they must be removed, hand hygiene performed, and a new pair put on
• Step by step procedure for removing soiled gloves

  1. Grasp the outside of one glove at the wrist (do not touch your bare skin)

  2. Peel the glove away from your body, pulling it inside out

  3. Hold the glove you removed in your gloved hand

  4. Peel off the second glove by putting your fingers inside the glove at the top of your wrist

  5. Turn the second glove inside out while pulling it away from your body, leaving the first glove inside the second

  6. Dispose of the gloves safely (do not reuse)

  7. Clean your hands immediately after removing gloves
• Personal Protective Equipment (PPE)

  • Includes gloves, laboratory gowns, mask, face shield, and goggles
  • Wearing of PPE is one of the most important aspects in performing laboratory work-ups
• Laboratory gowns


  • Worn to protect the clothing and skin of healthcare workers from contamination
  • Must be full body coverage
  • Should be put on first
  • Removed by pulling from the shoulder towards the hands, turned inside-out
  • Isolation gown should be tied on the back, laboratory gown should be buttoned down
• Masks, goggles, face shields

  • Worn to protect against inhalation of droplets containing pathogens from infective patients
  • Removed by unhooking the tie from the ears
  • Respirators (masks, goggles, and face shield in one) are individually-fitted and used when collecting blood from patients with airborne/air droplet diseases
  • N95 is the NIOSH-approved respirator
• Gloves


  • Used as protection from contamination by patient body substances
  • Used to protect patients from possible microorganisms on the healthcare worker's hands
• Donning of PPE


  1. Identify and gather the proper PPE

  2. Perform hand hygiene

  3. Put on a laboratory/isolation gown

  4. Put on a mask (surgical mask, N95, respirators, etc.)

  5. Put on a face shield or goggles

  6. Put on gloves
• Doffing of PPE


  1. Remove gloves

  2. Remove gown

  3. Perform hand hygiene

  4. Remove face shields or goggles

  5. Remove and discard the mask (surgical mask, N95)

  6. Perform hand hygiene after removal of mask
• Phlebotomist is responsible for blood sample collection and should be familiar with materials used in blood collection
• Being knowledgeable in phlebotomy materials and order of draw helps prevent pre-analytical errors that will be encountered in the laboratory
• Phlebotomy or venipuncture is the act of obtaining a blood sample from a vein using a needle attached to a collection device or a stoppered evacuated tube
• General blood collection equipment and supplies

  • Phlebotomy Area/Chair
  • Equipment carrier/Phlebotomy Collection Tray/Tackle box
  • Syringe/ETS/Lancets
  • Tourniquet
  • Evacuated Collection Tubes
  • Gloves
  • Antiseptics/Disinfectants/Hand Sanitizers
  • Gauze pads/Cotton
  • Bandages
  • Sharps container
  • Biohazard bags
  • Marking pen
• Requisition form is used during the identification process of each patient and is required prior to the venipuncture procedure
• Phlebotomy needles


  • Sterile and single use
  • Needle gauge (20-23 Gauge) is appropriate for venipuncture
  • Length is 1-1.5 inches
  • Gauge is 16-25
  • Three types: Multi-sample, Hypodermic, Winged infusion set
  • Needle position is 15 to 30 degrees angle
  • 21 gauge with 1.5 inches is the standard for adult venipuncture
• Syringe system


  • Used as an alternative method when drawing blood
  • Preferred method when drawing blood from patients with small or fragile veins
  • Suction pressure on the vein can be controlled
  • Routinely used: 2mL, 5mL, 10mL
  • Composed of syringe needle with plastic hub and syringe divided into graduated barrel and plunger
• Evacuated tube system


  • Closed collection system, most efficient and most frequently used method for venipuncture
  • Blood is collected directly into the evacuated tube
  • Enables multiple tubes to be collected in a single venipuncture
  • Composed of multi-sample needle, tube holders, and evacuated tubes with pre-measured vacuum
• Butterfly system


  • Winged infusion set or winged collection set
  • Used for IV fluid infusion and venipuncture for small and fragile veins (pediatrics, geriatrics)
  • Has a short needle with a plastic part resembling butterfly wings
  • Needle size is 1/2 to 3/4 inches
  • With long tubing with luer fitting and luer adapter
• Skin puncture devices


  • Manual lancets
  • Automatic puncture devices that deliver a swift puncture to a predetermined depth
  • Contact activated
• Evacuated collection tubes


  • May be plastic or glass with a colored rubber top
  • Color indicates the specific diagnostic test to be performed
• Microcollection tubes


  • Used for dermal puncture samples
  • Available with capillary tube fitted inside the container to aid in the collection of the sample
• Tourniquet


  • Vein compressor used to allow the vein of interest to become easily palpable and visible to the phlebotomist
  • Should be less than one minute and 3-4 inches above the puncture site
  • Longer application can cause hemoconcentration
• Vein locating devices


  • Transillumination portable devices that use infrared light to help health professionals locate and assess veins for safe venous access
• Antiseptics


  • Commonly used to disinfect the area to be punctured for the collection of blood
  • Examples: 70% ethyl/isopropyl alcohol, benzalkonium chloride, chlorhexidine gluconate, hydrogen peroxide, povidone-iodine, tincture iodine
• Disinfectants


  • Example: 10% sodium hypochlorite
• Gauze pads or cotton balls are used by phlebotomists to apply pressure to the venipuncture site and maintain sterilization
• Adhesive bandages are placed over the puncture site when the bleeding has stopped or when more pressure is required
• Blood collection tube additives

  • Anticoagulants (prevent blood clots)
  • Antiglycolytic agents (prevent breakdown of glucose)
  • Clot activators (enhance coagulation)
  • Thixotropic gel separator (inhibits cellular metabolism)
  • Trace element-free tube (few trace element contamination)
• Common stopper colors, additives, and departments involved

  • Light blue (sodium citrate) - Coagulation
  • Red (glass, no additive) - Chemistry, Blood bank, Serology/Immunology
  • Red (plastic, clot activator) - Chemistry
  • Red/Light Gray (plastic, nonadditive) - NA (Discard Tube only)
  • Red/black (Tiger, clot activator and gel) - Chemistry
  • Gold, Red/Gold (separator) - Chemistry
  • Green/Gray, Light Green (lithium heparin and gel separator) - Chemistry
  • Green (lithium heparin, sodium heparin) - Chemistry
  • Lavender, Pink (EDTA) - Hematology, Blood bank
  • Gray (sodium fluoride and potassium oxalate) - Chemistry
• Coagulation is enhanced by clot activators