What is true about the vertical flow laminar hood in sterile compounding?

• A. It can be used for sterile compounding.
• B. It cannot be used for sterile compounding.
• C. There are no restrictions on its use.
• D. It is always the best option for sterile compounding.

Answer: (B)

Airflow direction is what determines whether a hood can maintain a sterile field. A vertical flow laminar hood pushes clean air downward onto the work surface, but because the front is open to the room and the operator, contaminants from hands, arms, and room air can enter the critical area and turbulence can develop near the front of the hood. Sterile compounding relies on a unidirectional, crossflow of clean air that sweeps particulates away from the sterile field; horizontal-flow hoods (air moving from back to front) are designed to provide that protection. Because a vertical flow hood does not reliably uphold that crossflow protection for sterile preparations, it is not used for sterile compounding in standard practice.