Procedure: Obtaining a CSF Sample from an External Ventricular Drainage Device


Ensure that patient and health care provider safety standards are met during this procedure including:

  • Risk assessment and appropriate PPE
  • 4 Moments of Hand Hygiene
  • Procedural Safety Pause is performed
  • Two patient identification
  • Safe patient handling practices
  • Biomedical waste disposal policies
  1. Obtain Equpment and order test
  2. Clamp the catheter
  3. Prepare Sampling Port
  4. Collect Specimen
  5. Complete Order



Obtain Equipment

  • PPE
  • Clean gloves
  • Sterile towel
  • Chlorhexidine 2% with 70% alcohol swab stick
  • 3 ml luer-lock syringe
  • Sterile specimen container (with orange lid)
  • Order labels for CSF culture and STAT GRAM STAIN
Figure 1.01: Codman EDS 3 tubing showing patient connection, CSF sampling port, patient stopcock and slider clamps.


Clamp The Catheter for Five Minutes

  1. Perform hand hygiene
  2. Open the outer wrap of the sterile towel 
  3. Don clean gloves
  4. Identify the CSF sampling port (red end)
  5. Identify the slide clamp on either side of the CSF sampling port
  6. Clamp the slide clamp that is located between the CSF sampling port and the drainage collecting chamber.
  7. Maintain the clamp for 5-10 minutes only. Monitor the ICP while clamped.  If the ICP increases and exceeds the ICP target, collect the sample  and reopen the clamp.

Clamping the catheter allows the ventricle to fill with CSF prior to sampling. This increases the ability to obtain a specimen and may decrease the risk of generating a negative pressure within the ventricle.


Figure 1.02: Close slide clamp between CSF sampling port and drainage collecting unit.


Prepare the sampling port

  1. Open chlorhexidine/alcohol swab stick package
  2. With your non-dominant hand, lift the tubing near the CSF sampling port off the bed.
  3. Open up the green towel to create a sterile field.
  4. Scrub the red CSF sampling port hub vigorously with chlorhexidine/alcohol, then scrub the remainder of the red cap. Turn the swab stick over and clean the tubing from the sampling port to the slide  clamp.
  5. Place the cleaned tubing onto the sterile field, ensuring the sampling port is completely dry and is protected from any contact.


Collect Sample

Collect sample 5 - 10 minutes after clamping as follows (or earlier if ICP increases above target):

  1. Connect a syringe to the luer-lock connection of the red CSF sampling port
  2. With clamp on, gently attempt to aspirate CSF. . 
  3. If CSF does not flow easily into the syringe, open the clamp and reattempt aspiration.
  4. Obtain 1 - 2 ml of CSF.
  5. Empty the syringe into an orange sterile specimen container. The lab will not accept specimens in syringes due to risk for spillage/exposure of body fluids.
  6. Verity patient ID and label specimen at bedside.
  7. Ensure that the slide clamp is completely reopened.
  8. Reassess ICP and ICP waveform.
Figure 1.03: Gently aspirate CSF into the syringe


Complete Order

  1. Ensure sample goes to lab STAT.
  2. Document completion and patient response in the EHR under assess/reassess.

Developed by:
Brenda Morgan 
August 17, 2006

Last Update:  January 31, 2020; Reviewed: February 4, 2021; Revised January 31, 2024

AANN (2011). Care of the Patient Undergoing ICP/EVD or LD. AACN. Retrieved from (January 31, 2020):