Lean methods to improve operating room elective first case on-time starts in a large, urban, safety net medical center. 
Delays in first cases contribute to multiple operating room (OR) inefficiencies and decreases in OR productivity.  Lean process improvement methods were used to redesign the existing workflow for elective first cases of the day in a large, urban, public hospital.  First case start times were prospectively recorded from May 2, 2016 through December 29, 2017.  Data from 415 operating days were examined, 86 days prior to, 35 days during, and 294 days after implementation of interventions in the pre-operative holding area.  During this time, of 23,891 operations performed, 14,981 were elective procedures, 5963 (39.8%) of which were first cases of the day.  The mean rate of elective first case on-time starts per week went from 23.5% before and during to 73.0% after implementation of lean interventions (p < 0.0000001).  Implementation of lean interventions in the pre-operative holding area was associated with significantly improved rates of elective first case on-time starts.