What is the contact time for chlorhex?

• A. 3 minutes
• B. 1 minute
• C. 5 minutes
• D. 2 minutes

Answer: (D)

The main idea is how long chlorhexidine needs to stay on the skin to achieve effective antisepsis before surgery. Chlorhexidine works best when it’s given enough dwell time on the skin for its antimicrobial action to take effect. For routine preoperative skin antisepsis, about two minutes of contact time is recommended. This allows the agent to interact with the skin flora and reduce microbial load, while also enabling the antiseptic to dry and leave residual activity that helps continue to protect the area.

Choosing a shorter duration, like one minute, may not give the full antimicrobial effect, whereas longer durations (three or five minutes) aren’t typically required for standard prep and would unnecessarily delay the procedure. That’s why two minutes is considered the best answer.