PMLS2 LAB FINALS

• Capillary Puncture


  Procedure to obtain small amounts of blood from a finger or heel for testing
• Capillary Puncture Equipment


  • Lancet/Incision Devices
  • Micro collection Containers/ Microtubes
  • Microhematocrit Tubes and Sealants
  • Capillary Blood Gas Equipment
  • Microscope slides
  • Warming devices
• Lancet/Incision Devices


  • Sterile, disposable, sharp-pointed or bladed instrument to obtain capillary blood specimens for testing
  • Available in a range of lengths and depths to accommodate various specimen collection requirements
  • Specifically designed for either finger puncture or heel puncture
• Types of finger puncture lancets

  • BD Microtainer® contact activated lancets
  • Tenderlett® toddler, junior, and adult lancets
  • Capiject® safety lancets
  • ACCU-CHEK®
• Micro collection Containers/ Microtubes

  • Small plastic tubes used to collect the tiny amounts of blood obtained from capillary punctures
  • Often referred to as "bullets"
  • Most have color-coded bodies or caps/stoppers (correspond to color coding of ETS blood collection tubes)
• 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
  • Fill by capillary action and typically hold 50 to 75 μL of blood
  • Heparin tubes typically have a red or green band on one end
  • Nonadditive tubes have a blue band
  • Plastic, clay, or wax-type sealants that come in small trays are used to seal one end of microhematocrit tubes
• Capillary Blood Gas Equipment


  • CBG collection tubes: Long thin narrow-bore capillary tubes, most common are 100 mm in length with a capacity of 100 μL, inside coated with heparin, identified by a green band
  • 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 caps: 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


  • Warming the site increases blood flow as much as seven times
  • To avoid burning the patient, the devices provide a uniform temperature that does not exceed 42°C
  • A towel or diaper dampened with warm tap water can also be used to wrap a hand or foot before skin puncture
• 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
• Specimens for newborn screening tests should be collected separately and from a separate puncture site
• 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 Puncture Procedures


  • Heel punctures
  • Fingerstick procedure
• Capillary Blood Gases


  • Less desirable for blood gas analysis due to its only partial arterial composition
  • Temporarily exposed to air during collection, which can alter test results
• Capillary Puncture Procedures


  1. Heel punctures

  2. Fingerstick procedure
• Special Capillary Puncture Procedures

  • Capillary Blood Gases - Less desirable for blood gas analysis, its only partial arterial composition, temporarily exposed to air during collection, which can alter test results
  • Neonatal Bilirubin Collection - Commonly tested to detect and monitor increased bilirubin levels, specimens must be collected quickly to minimize exposure to light and must be protected from light during transportation and handling
  • Newborn/Neonatal Screening - 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
• Newborn/Neonatal Screening


  1. Specimens for NBS tests are collected by heel puncture and require a special state form

  2. Most NBS tests are ideally performed when an infant is between 24 and 72 hours old
• Newborn Screening Blood Spot Collection
• Phenylketonuria


  Genetic disorder, 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, PKU testing typically requires the collection of two specimens, one shortly after an infant is born and another after the infant is 10 to 15 days old
• 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, positive results are confirmed by measuring thyroid-stimulating hormone (TSH) levels, the disorder is treated by supplying the missing thyroid hormone orally
• 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, several less severe forms of galactosemia that may not need treatment can also be detected by newborn screening
• 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, early diagnosis and treatment helps avoid respiratory distress and malnutrition and has the potential to increase life expectancy
• Routine Blood Film/Smear Preparation

  1. Thin Blood film/smear - A drop of blood spread thin on a microscope slide, required to perform a manual differential (Diff)

  2. Thick smear - Most often requested to detect the presence of malaria, a few special tests require evaluation of a blood smear made from a fresh drop of blood from a fingertip
• Thin Smear


  To prepare a smear manually from an EDTA specimen, the tube of blood must first be mixed for a minimum of 2 minutes to ensure a uniform specimen, a plain capillary tube or pipet is then used to dispense a drop of blood from the specimen tube onto the slide, a device called DIFF-SAFE allows a slide to be made from an EDTA tube without removing the tube stopper
• Thick Smear


  Malaria is diagnosed by the presence of the organism in a peripheral blood smear, to prepare a 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, the smear is allowed to dry for a minimum of 2 hours before staining with fresh diluted Giemsa stain
• 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 for 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
• All body fluid specimens should be considered infectious and collected, transported, and handled according to safety protocols
• Urine


  By-product or fluid generated by the kidneys, carried to the urinary bladder via the ureter, and expelled by the urethra
• 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
• Urine specimens should be analyzed within


  of collection
• Allow urine sit at RT for at least

  minutes before testing
• Types of Urine Specimens

  • Random
  • First morning/8-hour urine specimen
  • Fasting
  • Timed
  • Tolerance test (glucose)
  • 2-hour postprandial
  • 24-hour
  • Double-voided
• 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
• Abnormal urine transparencies

  • Slightly hazy
  • Hazy
  • Cloudy
  • Very cloudy
  • Turbid
  • Cells or crystals, cellular elements
• Nonpathological causes of Urine Turbidity

  • Squamous epithelial cells
  • Mucus
  • Amorphous phosphates, carbonates, urates, spermatozoa
  • Fecal contamination
  • Radiographic contrast media
  • Talcum powder
  • Vaginal creams
• Pathological causes of Urine Turbidity

  • RBCs
  • WBCs
  • Bacteria
  • Parasite
  • Yeast
  • Non squamous epithelial cells
  • Abnormal crystals
  • Lymph fluid Lipids