PMLS LAB 2 FINALS 2.0

• Butterfly needle

  Short needle with "wings" attached to a piece of plastic tubing, used for fragile veins or pediatric draws
• Butterfly needle


  • Used for the infusion of IV fluids and for performing venipuncture from very small or very fragile veins often seen in children and in the geriatric population
  • Usually 21 or 23 gauge with lengths of 1/2 to ¾ inch
  • Plastic attachments to the needle that resemble butterfly wings are used for holding the needle during insertion and provide the ability to lower the needle insertion angle when working with very small veins
• Inserting the needle into the vein

  1. Insert the needle bevel up

  2. Use a shallow 10° to 15° angle

  3. Note a flash or small amount of blood that will appear in the hub of the needle when the needle is in the vein

  4. "Seat" the needle by threading it within the lumen of the vein

  5. Hold the needle with the thumb of the opposite hand
• Filling the tubes

  1. Leave the tourniquet in place until the last tube is filled, as long as the draw takes less than 1 minute

  2. Keep the tube holder in a downward position so the tube fills from the bottom up
• Withdrawing the needle

  1. Place gauze over the site

  2. Do not press down on the gauze while the needle is in the vein

  3. Withdraw the needle in one smooth motion

  4. Apply pressure on the site with gauze pad

  5. Do not bend arm up—keep it extended or raised
• Lancet/Incision devices


  Sterile, disposable, sharp-pointed or bladed instrument to obtain capillary blood specimens for testing
• Micro collection containers/microtubes


  Small plastic tubes used to collect the tiny amounts of blood obtained from capillary punctures
• Microhematocrit tubes and sealants

  • Disposable, narrow-bore plastic, or plastic-clad glass capillary tubes used primarily for manual hematocrit (Hct), also called packed cell volume (PCV), determinations
  • Plastic, clay, or wax-type sealants that come in small trays are used to seal one end of microhematocrit tubes
• Capillary blood gas equipment


  • Long thin narrow-bore capillary tubes coated with heparin, identified by a green band on the tube
  • Stirrers inserted into the tube after the blood is collected to aid in mixing the anticoagulant
  • Magnets used to mix the specimen after both ends of the tube have been sealed
  • Plastic cups used to seal CBG tubes and maintain anaerobic conditions in the specimen
• Microscope slides


  Occasionally used to make blood films for hematology determinations
• Warming devices


  Provide a uniform temperature that does not exceed 42°C to increase blood flow and avoid burning the patient
• Capillary specimens


  • Mixture of arterial, venous, and capillary blood, along with interstitial fluid and intracellular fluid
  • Capillary blood resembles arterial blood in composition
  • Composition of capillary blood differs from that of venous blood, reference (normal) values may also differ
• Order of draw

  1. Blood gas specimen

  2. EDTA specimens

  3. Other additive specimen

  4. Serum specimens
• General capillary puncture steps

  1. Review and Accession Test Request

  2. Approach, Identify, and Prepare Patient

  3. Verify Diet Restrictions and Latex Sensitivity

  4. Sanitize Hands and Put on Gloves

  5. Position Patient

  6. Select the Puncture Site

  7. Warm the Site if Applicable

  8. Clean and Air-Dry Site

  9. Prepare Equipment

  10. Grasp the Finger or Heel Firmly

  11. Position Lancet, Puncture Site, and Discard Lancet

  12. Lower Finger or Heel and Apply Gentle Pressure Until a Blood Drop Forms

  13. Wipe Away the First Blood Drop

  14. Fill and Mix Tubes/Containers in Order of Draw

  15. Place Gauze, Elevate Site, and Apply Pressure

  16. Label Specimens and Observe Special Handling Instructions

  17. Check the Site and Apply Bandage

  18. Dispose of used and Contaminated Materials

  19. Thank Patient, Remove Gloves, and Sanitize Hands

  20. Transport Specimen to the Lab Promptly
• Do not apply bandages to infants and children under 2 years of age because they pose a choking hazard. In addition, bandage adhesive can stick to the paper-thin skin of newborns and tear it when the bandage is removed.
• Capillary blood gases


  Less desirable for blood gas analysis due to its only partial arterial composition and temporarily exposed to air during collection, which can alter test results
• Newborn/neonatal screening


  1. Mandated testing of newborns to detect certain genetic, metabolic, hormonal, and functional disorders or conditions that can cause severe mental handicaps or other serious problems if not detected and treated early

  2. Most NBS tests are ideally performed when an infant is between 24 and 72 hours old

  3. Specimens for NBS tests are collected by heel puncture and require a special state form
• Five groups of disorders that can be detected by newborn screening

  • Phenylketonuria
  • Hypothyroidism
  • Galactosemia
  • Cystic fibrosis
• Phenylketonuria


  Genetic disorder with a defect in the enzyme that breaks down the amino acid phenylalanine, converting it into the amino acid tyrosine. If left untreated or not treated early on, phenylalanine can rise to toxic levels and lead to brain damage and mental retardation.
• Hypothyroidism


  Insufficient levels of thyroid hormones. If left untreated, the deficiency hinders growth and brain development. Newborn screening tests detect both inherited and non inherited forms.
• Galactosemia


  Characterized by lack of the enzyme needed to convert the milk sugar galactose into glucose needed by the body for energy. Untreated, the infant may starve to death. Untreated infants that survive typically fail to grow, are mentally handicapped, and have cataracts.
• Cystic fibrosis


  Caused by one or more mutations in the gene that directs a protein responsible for regulating the transport of chloride across cell membranes. Mutation causes the body to produce thick, sticky mucus secretions that build up in the lungs and other organs.
• Thin blood film/smear


  A drop of blood spread thin on a microscope slide, required to perform a manual differential (Diff)
• Thick smear


  A very large drop of blood is placed in the center of a glass slide and spread with the corner of another slide or cover slip until it is the size of a dime, used to diagnose malaria by the presence of the organism
• Blood smears prepared from EDTA specimens should be made within 1 hour of collection to eliminate cell distortion caused by the anticoagulant.
• Non-blood specimens in laboratory

  • Urine
  • Amniotic Fluid
  • Cerebrospinal fluid
  • Gastric fluid
  • Nasopharyngeal secretions
  • Saliva
  • Semen
  • Serous fluid
  • Sputum
  • Sweat
  • Buccal swabs
  • Bone marrow
  • Breath samples
  • Feces
  • Hair
  • Throat swabs
  • Tissue specimen
• Urine


  By-product or fluid generated by the kidneys, carried to the urinary bladder via the ureter, and expelled by the urethra. Major organic substances: Urea, Creatinine, Uric Acid. Major inorganic substances: Cl, Na, K.
• Routine urinalysis testing

  Describes the results of a series of screening tests capable of detecting (in a semi-quantitative manner) renal, urinary tract, metabolic and systemic diseases. Urine is readily available and easy to collect.
• Types of urine specimen

  • Random
  • First morning/8-hour urine specimen
  • Fasting
  • Timed
• Urine collection methods

  • Random Urine Collection
  • First Morning Urine Collection
  • Midstream Clean- Catch Collection
  • 24-hour Urine Collection
  • Timed Urine Collection
  • Catheterized Urine Collection
  • Suprapubic aspiration
  • Pediatric Urine Collection
• Urinalysis

  • Physical Examination
  • Chemical Examination
  • Microscopic Examination
• Physical examination of urine

  • Color
  • Clarity
  • Specific Gravity (1.005 – 1.030)
  • Odor
• Urine collection methods

  • Random Urine Collection
  • First Morning Urine Collection
  • Midstream Clean- Catch Collection
  • 24-hour Urine Collection
  • Timed Urine Collection
  • Catheterized Urine Collection
  • Suprapubic aspiration
  • Pediatric Urine Collection
• Urine collection types

  • Random
  • First morning
  • Midstream clean-catch
  • 24-hour
  • Timed
  • Catheterized
  • Suprapubic aspiration
  • Pediatric
• Timed urine collection

  1. Collected at specific times

  2. Pooled throughout a specific period
• Timed urine collection examples

  • Tolerance test (glucose) - fasting, 1⁄2hour, 1hour, etc.
  • 2-hour postprandial - two hours after a meal
  • 24-hour - collection and pooling of all urine that is voided in 24 hours
  • Double-voided - waiting time of approximately 30 minutes after emptying the bladder
• Fasting: a second morning or second specimen voided after fasting
• Physical examination of urine

  Examination of color, clarity, specific gravity, odor
• Normal urine color

  • Pale yellow to amber yellow
• Urine pigments


  • Urochrome (yellow)
  • Uroerthyrin (red)
  • Urobilin (orange-red)