Cluster coding
Cluster coding is a mechanism of linking related diagnosis codes through use of a diagnosis cluster identifier (DCID) that will enhance the value of coded data.
Why is cluster coding necessary?
While clinical coders assign and sequence codes, the relationship between codes is not always evident when the coded data is analysed. Assigning codes in sequence does not always indicate a relationship and sometimes that sequencing is not retained when the data is processed and validated by information technology (IT) systems.
With cluster coding, the relationship between codes becomes clearer which adds meaning and improves the utility of the data.

How will cluster coding work?
Cluster coding is proposed to be implemented in a staged approach. In stage one, conditions requiring external cause codes, and supplementary codes for chronic conditions will be assigned to specific clusters. The remaining codes will be assigned a value denoting they are not part of a specific cluster.

Support for implementation
To support the implementation of cluster coding, the Independent Health and Aged Care Pricing Authority (IHACPA) will provide the following:
- Guidelines in the Australian Coding Standards (ACS)
Creation of ACS 0004 Diagnosis cluster identifier (DCID), to provide guidance on the purpose and application of cluster coding for Thirteenth Edition. - Pilot exercise to test the proposed ACS 0004 Diagnosis cluster identifier (DCID)
IHACPA will conduct a pilot exercise in early 2024 to test the proposed classification guidelines. - Enhancements to the electronic code lists (ECLs)
Thirteenth Edition ECLs will identify codes that require application of the DCID. Flagging relevant codes will assist software vendors in the application of the DCID and allow data collection agencies to formulate edits that will enhance the quality and application of the DCID. - Engagement with stakeholders
IHACPA will engage stakeholders through public consultation, public forums and will conduct industry briefings. - Education
Education on cluster coding will be available to clinical coders, health information managers, data users, clinical coding auditors and educators, software vendors and tertiary education providers through IHACPA Learn.
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