High level disinfectant is
**Core Concept**
A high-level disinfectant is a chemical agent used to eliminate a wide range of microorganisms from non-critical medical equipment and surfaces. This level of disinfection is typically required for equipment that comes into contact with mucous membranes or non-intact skin. The agent must be able to inactivate or destroy all viruses, fungi, and bacteria, except for certain bacterial spores.
**Why the Correct Answer is Right**
High-level disinfectants work by denaturing proteins, disrupting cell membranes, and interfering with metabolic processes. They are often quaternary ammonium compounds or phenolic compounds, which have a broad spectrum of antimicrobial activity. Examples of high-level disinfectants include glutaraldehyde, hydrogen peroxide, and orthophthalaldehyde. These agents are typically used for equipment that cannot be sterilized by heat or dry methods.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because low-level disinfectants, such as hypochlorite solutions, are not as effective against a wide range of microorganisms as high-level disinfectants.
**Option B:** This option is incorrect because antiseptics, such as povidone-iodine, are used to disinfect skin and mucous membranes, but are not used to disinfect medical equipment.
**Option C:** This option is incorrect because sterilants, such as ethylene oxide, are used to eliminate all forms of microbial life, including bacterial spores, and are typically used for equipment that cannot be disinfected.
**Clinical Pearl / High-Yield Fact**
When using high-level disinfectants, it is essential to follow proper protocols, including adequate dwell time, temperature control, and rinsing, to ensure effective microbial inactivation.
**Correct Answer: D. Glutaraldehyde**