Principles of asepsis

Asepsis means freedom from pathogenic (that is, disease-causing) microorganisms, whilst sepsis indicates the presence of micro-organisms causing toxicity in the body.


Infection can occur endogenously or exogenously.

  • Endogenous – from sites on or in the host, for example from the client’s skin, nose, or intestines
  • Exogenous – from routes outside the host or environmental, such as:
    • airborne, for example droplets, dust, dressings, bedding
    • direct or indirect contact, for example hands, clothing, equipment, and food
    • percutaneously, for example intravenous infusions, needles.

In order to reduce the potential for exogenous infection, nurses and other health care professionals employ what is termed a sterile (or aseptic), nontouch technique when undertaking invasive procedures such as urethral catheterization and injections, or procedures where the risk of crossinfection is high, for example when dressing wounds or removing sutures and drains.


Aseptic or non-touch technique

  • Explain procedure to the client, ensure adequate understanding and obtain consent
  • Encourage the client to adopt an appropriate and comfortable position and loosen dressing(s) without exposing the patient unduly
  • Prepare the environment and allow airborne dust and micro-organisms to settle before proceeding
  • Put on appropriate plastic apron and wash hands thoroughly (see above)
  • Clean dressing trolley with alcoholic surface wipe or soap and water if debris evident, cleaning from top to bottom and drying thoroughly (refer to local policy)
  • Collect all equipment and place on bottom shelf of trolley
  • Take trolley/equipment to the client, disturbing the area as little as possible
  • Check the expiry date on sterile dressing pack; make sure it is intact and dry. Open the outer cover of the pack and slide the contents onto the trolley top
  • Open sterile field/paper using corners only and position over work surface


  • Position contents of pack then check and open any other packages, maintaining sterility of field
  • Remove soiled dressing(s) using forceps
  • Wash hands thoroughly using appropriate cleaning agent
  • If using sterile gloves apply now, touching only the inside of the cuff
  • Place sterile field around area, e.g. wound, perineum
  • Cleanse the wound if necessary
  • Apply and secure dressing as appropriate, ensuring client comfort
  • Dispose of clinical waste and instruments as per universal precautions and hospital policy
  • Dispose of apron and gloves, if worn, in appropriate receptacle
  • Wash and dry dressing trolley
  • Wash hands thoroughly
  • Document care given and report any changes or abnormalities in evaluation