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Intravascular Cannulae & Associated Specimens

Alias: Tips, Lines

Discipline: Clinical Microbiology

Test information: The detection and recovery of the causative bacterial and fungal organisms of Cannula-related infections. Where applicable to determine antimicrobial susceptibility results.

Availability: Available locally Monday - Sunday during routine hours: 08:45 - 17:15.

Turnaround Time: 48 hours (Culture)

Related Tests: Blood Culture

Specimen Type(s)
  • Central Lines;
  • Central Venous Catheter (CVP);
  • Hickman Lines;
  • Line tips;
  • PICC Lines;
  • Swabs of cannula insertion sites;
Other Acceptable Specimen Type(s)
Specimen Container - Adult
  • Sterile CE-marked Charcoal swab in Transport medium;
  • Sterile CE-marked Universal Container;
Specimen Container - Paediatric
  • Sterile CE-marked Charcoal swab in Transport medium;
  • Sterile CE-marked Universal Container;
  • Culture & Sensitivity;
Part of a test profile?
Volume (min) of sample to be sent to laboratory
Ideally 4cm
Patient Preparation, Sample Handling and Transport
  • Collect specimens before antimicrobial therapy where possible.
  • Disinfect the skin around the cannula entry site, remove cannula using aseptic technique, and cut off 4cm of the tip into a sterile container using sterile scissors.
  • For swabs, sample the inflamed area / exudate around the catheter insertion site.
  • Urinary catheter tips are NOT examined.
  • Cannulae should only be sent if there is evidence of infection.
  • Specimens should be transported to the laboratory without delay during normal working hours.
  • If transport is delayed store at 2-8 °C.
  • The swab must arrive in the laboratory within 24 hours of being taken.
Maximum add on time
Units and Reference Ranges / Interpretation

When testing the external surface of the cannula tip, a threshold of >15 colonies of any organism is commonly accepted to predict cannula-related sepsis and is associated with bacteraemia in 10-14% of cases.

Susceptibility Testing: Each susceptibility category is defined by breakpoints specific for each species and agent. The breakpoints are minimum inhibitory concentrations (MIC) and describe the amount of agent required to inhibit the growth of the organism.

The definitions of (S),(I), and (R) emphasize the close relationship between the susceptibility of the organism and the exposure of the organism at the site of infection.

Susceptible (S): High likelihood of therapeutic success with standard dosing.
Susceptible Increased Exposure (I): High likelihood of therapeutic success with increased dosing.
Resistant (R): High likelihood of therapeutic failure.

UKAS number
UKAS accredited test?

If you have any queries about a test or results interpretation please contact us.

Last updated: 01-06-2023