Assistant Laboratory Animal Technician (ALAT) Practice Exam

How does a biological safety cabinet primarily protect personnel from exposure to pathogens?

1. By using a high airflow rate

2. By maintaining positive pressure inside the cabinet

3. By filtering air through a HEPA filter before exhausting

4. By using ultraviolet light for sterilization

The correct answer is: By filtering air through a HEPA filter before exhausting

A biological safety cabinet primarily protects personnel from exposure to pathogens by filtering air through a HEPA filter before exhausting it. This process is essential as the HEPA filter is designed to capture airborne particles, including bacteria and viruses, ensuring that the air is effectively cleaned before it is released back into the laboratory environment. The use of high-efficiency particulate air (HEPA) filters allows the cabinet to provide a sterile environment, thus minimizing the risk of airborne transmission of infectious agents to the personnel working nearby. The cabinet operates under a negative pressure system, which means that air is drawn into the cabinet, preventing contaminated air from escaping into the laboratory. This is crucial in protecting personnel, as any pathogens generated within the cabinet are safely contained away from the operator. The design and filtration systems work together to create a safe working environment when handling potentially hazardous biological materials. In contrast, maintaining positive pressure or using ultraviolet light for sterilization do not directly address personnel protection from airborne pathogens in the same effective manner that HEPA filtration does. High airflow rates may not specifically ensure pathogen containment, while ultraviolet light serves a different purpose in disinfection rather than providing continuous protection during use.