Sterilization protocols require procedures that are not practical, or necessary, in many settings. Various other methods are used in clinical and nonclinical settings to reduce the microbial load on items. Although the terms for these methods are often used interchangeably, there are important distinctions.

The process of disinfection inactivates most microbes on the surface of a fomite by using antimicrobial chemicals or heat. Because some microbes remain, the disinfected item is not considered sterile. Ideally, disinfectants should be fast acting, stable, easy to prepare, inexpensive, and easy to use. An example of a natural disinfectant is vinegar; its acidity kills most microbes. Chemical disinfectants, such as chlorine bleach or products containing chlorine, are used to clean nonliving surfaces such as laboratory benches, clinical surfaces, and bathroom sinks. Typical disinfection does not lead to sterilization because endospores tend to survive even when all vegetative cells have been killed.

Unlike disinfectants, antiseptics are antimicrobial chemicals safe for use on living skin or tissues. Examples of antiseptics include hydrogen peroxide and isopropyl alcohol. The process of applying an antiseptic is called antisepsis. In addition to the characteristics of a good disinfectant, antiseptics must also be selectively effective against microorganisms and able to penetrate tissue deeply without causing tissue damage.

The type of protocol required to achieve the desired level of cleanliness depends on the particular item to be cleaned. For example, those used clinically are categorized as critical, semicritical, and noncritical. Critical items must be sterile because they will be used inside the body, often penetrating sterile tissues or the bloodstream; examples of critical items include surgical instruments, catheters, and intravenous fluids. Gastrointestinal endoscopes and various types of equipment for respiratory therapies are examples of semicritical items; they may contact mucous membranes or nonintact skin but do not penetrate tissues. Semicritical items do not typically need to be sterilized but do require a high level of disinfection. Items that may contact but not penetrate intact skin are noncritical items; examples are bed linens, furniture, crutches, stethoscopes, and blood pressure cuffs. These articles need to be clean but not highly disinfected.

The act of handwashing is an example of degerming, in which microbial numbers are significantly reduced by gently scrubbing living tissue, most commonly skin, with a mild chemical (e.g., soap) to avoid the transmission of pathogenic microbes. Wiping the skin with an alcohol swab at an injection site is another example of degerming. These degerming methods remove most (but not all) microbes from the skin’s surface.

The term sanitization refers to the cleansing of fomites to remove enough microbes to achieve levels deemed safe for public health. For example, commercial dishwashers used in the foodservice industry typically use very hot water and air for washing and drying; the high temperatures kill most microbes, sanitizing the dishes. Surfaces in hospital rooms are commonly sanitized using a chemical disinfectant to prevent disease transmission between patients.

A table titled: Common protocols for control of microbial growth. Four columns: protocol, definition, common application and common agents. The table is divided by protocols used for fomites and those used on living tissue. Protocols for fomites include disinfection, sanitation, and sterilization. Disinfection reduces or destroys microbial load of an inanimate item through application of heat or antimicrobial chemicals. Disinfection involves cleaning surfaces like laboratory benches, clinical surfaces, and bathrooms and uses Chlorine bleach, phenols (e.g., Lysol), glutaraldehyde. Sanitization reduces microbial load of an inanimate item to safe public health levels through application of heat or antimicrobial chemicals. Sanitation involves Commercial dishwashing of eating utensils, cleaning public restrooms and uses Detergents containing phosphates (e.g., Finish), industrial-strength cleaners containing quaternary ammonium compounds. Sterilization Completely eliminates all vegetative cells, endospores, and viruses from an inanimate item. Sterilization involves Preparation of surgical equipment and of needles used for injection and uses Pressurized steam (autoclave), chemicals, radiation. Protocols for living tissue include antisepsis and degerming. Antisepsis Reduces microbial load on skin or tissue through application of an antimicrobial chemical. Antisepsis involves Cleaning skin broken due to injury; cleaning skin before surgery and uses Boric acid, isopropyl alcohol, hydrogen peroxide, iodine (betadine). Degerming Reduces microbial load on skin or tissue through gentle to firm scrubbing and the use of mild chemicals. Degerming involves Handwashing and uses Soap, alcohol swab.