Critical instruments. Any instruments that enter sterile tissue or the vascular system (i.e. any object used in a surgical procedure. These must be sterile because any contamination could transmit disease. Critical instruments require high-level disinfection. This is the complete elimination of all microorganisms on an instrument, and is typically achieved by using a steam sterilizer. Any reusable medical instruments that are used to break intact skin (eg, nippers, forceps, splitters, and curettes) should be sterilized using steam rather than using chemical disinfectants. The CDC recommends that you test your sterilizer at least weekly, to verify that it is sterilizing properly. Visit www.WoodhouseLabs.com for more information. Semi-critical instruments. Any tool that comes into contact with non-intact skin, such as tissue nippers or curettes used for debridement of an ulceration or incision, and drainage of an abscess. These devices also require high-level disinfection.Non-critical instruments. Any tool that comes into contact with intact skin or nails. Since transmission of a disease is unlikely through intact skin, low-level disinfection is allowed. However, intermediate level disinfection is still recommended. Intermediate level disinfection destroys all vegetative bacteria, viruses and fungi but not bacterial spores. This is typically achieved by using iodophor, alcohol or chlorine.