The "American Taxpayer Relief Act of 2012” provides for a zero percent SGR update for services provided from January 1, 2013, through December 31, 2013. As a result, the unadjusted Medicare Anesthesia Conversion Factor for 2013 is $21.9243 instead of the previously released figure of $15.93. The unadjusted anesthesia conversion factor for services provided in 2012 was $21.520. The increase is due in part to the positive adjustments that have been phased-in over the past four years to incorporate changes in the practice expense component of anesthesia care as supported by ASA.