Wound Class

Guideline · Aug 2019 · 1 min read

About this guideline

Class I: Clean Wounds

Uninfected operative wounds with no breaks in sterile technique and no inflammation encountered. The respiratory, alimentary, genital, or urinary tracts are not entered. Examples include spinal fusion, thyroidectomy, ganglion incision, and hernia repair.

Class II: Clean-Contaminated Wounds

Operative wounds where respiratory, alimentary, genital, or urinary tracts are entered under controlled conditions without unusual contamination, with no breaks in sterile technique or inflammation. Examples include cholecystectomy, colon resection, tracheostomy, Malone/Mitrofanoff procedures, and incidental appendectomy.

Class III: Contaminated Wounds

Wounds involving major breaks in sterile technique, acute non-purulent inflammation, or open fresh accidental wounds less than four hours old with gross gastrointestinal spillage. Examples include non-perforated appendicitis, inflamed gallbladder with bile spillage, fresh open fractures without gross contamination, and fresh penetrating wounds.

Class IV: Dirty/Infected Wounds

Old traumatic wounds over four hours, trauma from contaminated sources, or cases where organisms causing post-operative infection were present in the operative field before surgery. Examples include perforated appendicitis, old contaminated open fractures, and drainage of intra-abdominal abscesses.

Statements in this guideline

Class I (Clean) wounds are uninfected operative wounds in which the respiratory, alimentary, genital or uninfected urinary tract is not entered, with no breaks in sterile technique and no inflammation encountered.
EstablishedClass I: Clean
Class II (Clean Contaminated) wounds are operative wounds in which the respiratory, alimentary, genital or urinary tracts are entered under controlled conditions and without unusual contamination, with no breaks in sterile technique and no inflammation encountered.
EstablishedClass II: Clean Contaminated
Class III (Contaminated) wounds include incisions with acute, non-purulent inflammation, major breaks in sterile technique, open fresh or accidental wounds less than four hours old, and gross spillage from the gastrointestinal tract.
EstablishedClass III: Contaminated
Class IV (Dirty) wounds include old traumatic wounds over four hours, trauma from a contaminated source or gross spillage of infected source, and cases where organisms causing post-operative infection were present in the operative field before the operation.
EstablishedClass IV: Dirty

Full text

Wound Class Definitions Class I: Clean•No breaks in sterile technique•No inflammation is encountered•An uninfected operative wound in which respiratory, alimentary, genital or uninfected urinary tract is not entered Updated 3/2019 Class II: Clean Contaminated•No breaks in sterile technique•No inflammation is encountered•An operative wound in which the respiratory, alimentary, genital or urinary tracts are entered under controlled conditions and without unusual contaminationExamples:Spinal fusion, thyroidectomy, ganglion incision, hernia repairExamples:Cholecystectomy, colon resection, tracheostomy, Malone/mitrofanoff, appendectomy (incidental, not inflamed) Class III: Contaminated•Major break in sterile technique•Incisions with acute, non-purulent inflammation•Open, fresh, or accidental wounds less than four hours old•Gross spillage from gastrointestinal tractExamples:Non-perforated appendicitis, inflamed gallbladder (bile spillage), open fracture (fresh, no gross contamination), penetrating wound (fresh) Class IV: Dirty•Old traumatic wounds over four hours•Trauma from a contaminated source or gross spillage of infected source•Organisms causing post-operative infection were present in the operative field before the operationExamples:Perforated appendicitis, open fracture (old, contaminated trauma), drainage of intra-abdominal abscess

Updated 3/2019 Wound Class Definitions Source: Zinn JL. Surgical Wound Classification: Communication is Needed for Accuracy. AORN Journal. 2012;95(2): 274-278

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