Surgical contamination classes

Invasive procedures are divided into four classes based on the level of contamination:

• Procedures in non-contaminated regions: The surgical site is "clean", i.e. not contaminated; the respiratory, gastrointestinal or urogenital tract is not involved (e.g. thyroid gland, heart or joint surgery)
• Clean-contaminated procedures: The body area is colonised, the flora is, however, less contagious; the respiratory, gastrointestinal or urogenital tracts are opened under controlled conditions (e.g. oropharyngeal, vaginal or bile duct surgery)
• Procedures in contaminated regions: Fresh wounds; surgeries on the lower gastrointestinal tract; incisions in contaminated defects
• Procedures in manifestly infected regions: Wounds with clinical infection (e.g. abscess or intestinal perforation) or devitalised tissue; surgeries in patients with multidrug-resistant bacteria