Here’s the lowdown on Mutually Exclusive edits from CMS.
"The Mutually Exclusive edit file included edits where two procedures could not be performed at the same patient encounter because the two procedures were mutually exclusive based on anatomic, temporal, or gender considerations."
In April 2012, CMS decided to simply the NCCI files and consolidate the mutually-exclusive file with the Column One-Column Two file, however, this did not eliminate the mutually exclusive edit type. It merely collapsed two files into one. Only one code from a mutually-exclusive edit-pair can be reported on a given date, unless the service was performed at a different session and a modifier is permitted for use. It does not require you choose one code over the other as in a Column One/Column Two edit pair, as indicated by having a code-pair modifier "1". Edits that have a code-pair modifier "2" require the modifier to be placed on the "component/Column Two code, when appropriate.