Disinfectant levels

High-level disinfection inactivates vegetative bacteria, mycobacteria, fungi and viruses. It is not reliable against large numbers of bacterial spores at the high-level disinfection exposure. The note’s “all” needs that spore limit. High-level disinfection is still different from sterilisation.

Intermediate-level disinfectants kill vegetative bacteria, including mycobacteria, and many fungi and viruses. They do not reliably kill bacterial spores. The exact spectrum depends on the product.

The handwritten contact-time cues are 20–30 min for high level and 10–15 min for intermediate level. These are not fixed times for the whole class. Match the product’s stated concentration, temperature and contact time to the device and intended use. The same chemical may reach different disinfection levels when its formulation, concentration or exposure changes.

Clean first so debris does not shield the organisms. Keep the item or surface in contact with the product for the full labelled time. Do not use a level name alone to choose the clock.

References

Renberg & Claeys, “Sterilization,” Johnston & Tobias, Veterinary Surgery: Small Animal, 2nd ed., PDF pp. 476, 481. CDC, Guideline for Disinfection and Sterilization in Healthcare Facilities, Table 1 and Glossary. Related study set: Antiseptic solutions plus patient and room preparation.