A surgical scrub should typically last 2-6 minutes to effectively reduce the microbial load on the hands and forearms. This duration allows the antiseptic agent to adequately penetrate skin crevices and remove transient and resident flora, thereby minimizing the risk of surgical site infections. Shorter scrubs, such as 30 seconds or 1 minute, are insufficient to achieve this microbial reduction, while excessively long scrubs may cause skin irritation without added benefit. Maintaining this recommended time frame ensures optimal hand antisepsis before sterile procedures.

Reference: Sabiston Textbook of Surgery, Townsend et al., 21st Edition.