CMS has published a notice correcting errors that appeared in the final CY 2010 rule updating the Medicare hospital outpatient prospective payment system (HOPPS) and the ambulatory surgical center (ASC) payment system.  Among other technical changes, the rule corrects Medicare ambulatory surgical center (ASC) payment rates that had been based on incorrect Medicare physician fee schedule payment amounts. The December 31, 2009 correction notice includes an updated ASC fee schedule.