ACHI is the national standard for procedure and intervention coding, based on the Medicare Benefits Schedule (MBS). Generally, the first five characters represent the MBS item number and the last two characters are allocated for each procedural concept derived from the MBS item description.
As ACHI chapters resemble the ICD-10-AM chapters, the full set of ACHI codes are available in the Corporate Reference Data System (CRDS) ICD-10-AM data set.