Should I use a High Level Disinfectant or Cold Sterilant for reprocessing heat-sensitive instruments?

Heat-sensitive instruments can be sterilized or high-level disinfected by soaking them in a liquid chemical germicide cleared by the FDA. When choosing between products to use for reprocessing patient care items, looking at Spaulding's Classification System for practice standards can help you choose the best product for your office.

There are three categories of patient-care items depending on their intended use and the potential risk of disease transmission. They are designated as:

  • Non-critical
  • Semi-critical
  • Critical

The chart below defines these categories.

Spaulding's Classification System

Category Description
Non-Critical Instruments and Devices
  • Contact Intact Skin
  • Clean and disinfect using a low to intermediate level disinfectant
  • Examples: X-ray heads, facebows, pulse oximeter, blood pressure cuff
Semi-Critical Instruments
  • Contact mucous membranes but do not penetrate soft tissue
  • Heat sterilize or high-level disinfect
  • Examples: Dental mouth mirrors, amalgam condensers, and impression trays
Critical Instruments
  • Penetrate mucous membranes or contact bone, the bloodstream, or other normally sterile tissues (of the mouth)
  • Sterilize between uses or use sterile single-use, disposable devices
  • Examples: Surgical instruments, scalpel blades, periodontal scalers, and surgical dental burs

Understanding the categories and risk of transmitting infection is just one component of the question. Understanding the different products available and choosing the product that works best in your office is another component. There are many cold sterilants and high hevel disinfectants to choose from.

We've researched the market for you and have narrowed down the choices, making your job much easier. The chart below includes information on various types of germicidal solutions, the intended use, and features and benefits.

High Level Disinfection


The disinfecting mechanism of Ortho-phthalaldehyde (OPA) is thought to be similar to glutaraldehyde. A notable difference is the percent of active ingredient in each product. Although OPA may pose similar occupational hazards to glutaraldehyde, the risk is significantly reduced due to the low percentage of OPA and relatively low vapor pressure of OPA-based products.
We Recommend: Things to Consider:
Rapicide OPA/28
  • Use on non-critical and semi-critical items
  • Ready-to-use
  • Fast, 10 minute high level disinfetion
  • Maximum reuse period of 28 days
  • 75 day shelf like once open
  • Excellent materials compatibility
  • Non-corrosive to metal
  • Far less odor and irritation than glutaraldehydes
  • Test strips available
  • Inexpensive Glycine Neutralizer available for disposal


Cold Sterilization Solutions


Glutaraldehyde is used as a cold sterilant to disinfect heat sensitive instruments. It has been commonly used for years, is effective and inexpensive. It has a pungent odor and can cause repiratory problems if there isn't proper ventilation.
We Recommend: Things to Consider

Medica 28 Plus

  • Use on semi-critical or critical items
  • 2.5% glutaraldehyde advanced formuation reduces vapors
  • Liquid activator assures a mild, fresh scent
  • 90 minute high level disinfection
  • 10 hour sterilization
  • Maximum reuse period of 28 days
  • Contains a rust inhibitor
  • Aldex Neutralizer available for disposal

Hydrogen Peroxide

Hydrogen peroxide is another chemical sterilizing agent. Hydrogen peroxide is strong oxidant and these oxidizing properties allow it to destroy a wide range of pathogens and it is used to sterilize heat sensitive articles. Since hydrogen peroxide is a strong oxidant, there are material compatibility issues.
We Recommend: Things to Consider
Sporox II
  • Use on semi-critical or critical items
  • 7.5% Hydrogen Peroxide base
  • Ready-to-use
  • 30 minute high level disinfection
  • 6 hour sterilization
  • Maximum reuse period of 21 days
  • No noxious odors.
  • Will not bond infectious proteins to instruments.
  • Should not be used with brass, copper, nickel/silver plating and zinc
  • Test strips available
  • Neutralize with baking soda for disposing

Hydrogen Peroxide + Peracetic Acid

Peracetic Acid is also an oxidizing agent. Often mixed with hydrogen peroxide, peroxyacetic acid is used as a disinfectant and sanitizer
  • Use on semi-critical or critical items
  • 7.35% Hydrogen peroxide, 0.23% peracetic acid
  • Ready-to-use
  • 15 minute high level disinfection
  • 3 hour sterilization
  • Maximum reuse period of 14 days

Confusing? Please feel free to give us a call to discuss your specific needs. We are here to help! 

Be on the lookout for our next blog post where we discuss testing and disposal of High Level disinfectants and Cold Sterilants.