Paediatric capillary blood gas sampling [advanced]


  • Wash hands, Introduce self, Patients name & DOB, Explain procedure and obtain consent form parents (or child if appropriate)
Paediatric capillary blood gas equipment

Preparation part

  • Wash hands  
  • Clean tray
  • Gather equipment around tray (think through what you need in order)

Equipment list

  • Gloves
  • Vaseline (if available)
  • Alcohol 70%/chlorhexidine 2% skin cleansing wipe
  • Sterile lancet/puncture system
  • Capillary sample collection tube (with bungs and magnet rod)
  • Cotton gauze swabs
  • Tape

  • Wash hands
  • Open packets and place equipment neatly in tray in plastic parts of packets
  • Return to patient (with tray and sharps bin)

Patient part


  • Wash hands and apply gloves
  • Identify appropriate site:
    • Lateral or medial plantar heel (in young infant)
    • Medial or lateral border of finger pulp (in older child)
  • Apply Vaseline to area if available (to prevent blood globule dispersing in skin ridges)
  • Warm the area
  • If using the foot, hold the ankle dorsiflexed with one hand
  • Sterilise area – wipe in spiral motion working outwards and wait 30 seconds for it to dry


  • Puncture skin with lancet/puncture system (then drop into sharps bin)
  • Wipe off the first drop of blood with cotton gauze
  • Once a blood globule has built up, holding the sample collection tube horizontally, press the end gently onto the globule of blood until the blood enters the tube
  • Then move the collection tube away until the next globule has accumulated, then press the end onto the globule again
  • Repeat this until the tube is filled
  • Tips:
    • If blood if not forming freely, gently massage the area to encourage blood flow and gently squeeze the lower leg/ankle or digit (but let the capillaries refill intermittently)
    • Intermittently dab the area with cotton gauze swab to prevent coagulation of any blood left near the puncture site
    • There must not be any air bubbles in the tube or the gas machine will not be able to analyse it – keep the tube horizontal at all times to avoid this
  • Once tube is full
    • Insert magnet rod into one end and place a bung on each end, then mix by inverting it slowly and label it with a patient ID sticker
    • Place gauze over the puncture site and tape down or apply plaster

To complete

  • Thank patient and cover them
  • Take sample to blood gas analyser immediately
    • Remove bungs
    • Place adaptor onto one end to allow insertion into blood gas analyser
    • Enter patient information and await printed results
  • Bin waste and gloves, clean tray and wash hands
  • Document procedure and results in patients notes

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