Final answer:
The minimum level of asepsis required for reprocessing a contaminated endoscope is chemical sterilization, as endoscopes are semicritical items needing high-level disinfection or sterilization.
Step-by-step explanation:
The medical assistant is reprocessing a contaminated endoscope, and the minimum level of asepsis required for this instrument is chemical sterilization. Considering that an endoscope is classified as a semicritical item, it comes in contact with mucous membranes but does not penetrate sterile tissue; therefore, it requires high-level disinfection at a minimum. However, the best practice is to achieve sterilization where possible to ensure the complete removal or killing of all vegetative cells, endospores, and viruses. Sterilization can be accomplished through physical means, such as steam under pressure in an autoclave, or by using chemical sterilants. For the minimum level of asepsis required, chemical sterilization using high-level disinfectants or chemical sterilants capable of destroying all forms of microbial life is the baseline protocol for endoscopes.