Registered Dental Assistant (RDA) Law and Ethics Practice Exam

Which class of disinfection is the least effective against tuberculosis?

1. Low-level disinfection

2. Intermediate-level disinfection

3. High-level disinfection

4. Full-spectrum disinfection

The correct answer is: Low-level disinfection

Low-level disinfection is recognized as the least effective class against tuberculosis due to its limited ability to eliminate more resilient pathogens. This class primarily targets non-enveloped viruses and vegetative bacteria, but it does not have the potency required to inactivate mycobacteria, such as those that cause tuberculosis. Tuberculosis bacteria, Mycobacterium tuberculosis, have a waxy cell wall that provides them with a level of protection, making them more resistant to many disinfection methods. High-level disinfection and intermediate-level disinfection are equipped to address mycobacteria due to the presence of more powerful chemical agents and processes. Therefore, while low-level disinfection may suffice for routine cleaning, it falls short in the context of preventing the highly contagious and resilient tuberculosis from persisting on surfaces or instruments. This distinction is critical in dental and medical settings, where sterility and sanitation are paramount for patient safety.