When the principal diagnosis is one of these 18 codes, the CC/MCC codes assigned to this list count as non-CCs (MS-DRG v44 definitions manual, appendix C).
T23.301AT23.302AT23.309AT23.321AT23.322AT23.329AT23.391AT23.392AT23.399AT23.701AT23.702AT23.709AT23.721AT23.722AT23.729AT23.791AT23.792AT23.799A