Health data standards and systems

When a doctor lists several conditions as principal diagnosis my understanding of this standard has always been that we take into consideration the circumstances of the admission when choosing the principal diagnosis, as per example 1 in the standard (where I interpret all diagnoses as meeting criteria for coding). If, after viewing the notes, more than one diagnosis could equally be principal, as determined by admission circumstances, workup and therapy provided, we should refer to the clinician and, if no further information is available, choose the first listed as principal.

A recent in-house coding audit has revealed some coders consider that, provided all listed conditions meet the criteria for coding, they should refer the case to the doctor to advise which diagnosis is principal, otherwise, choose the first listed diagnosis.

A case in question involved the choice of NSTEMI or Acute on Chronic renal failure as principal, listed in that order by doctor. Patient notes refer to:
- Patient admitted under Renal Unit for acute worsening of renal failure. He had dehydration, chest pain and raised troponin in ED.
- ED admitting diagnosis = ARF
- First admission note is by Renal physician
- First nursing note-'transferred to ward from ED for ARF'
- Med. cover note - ATSP for chest pain while in ED. Admitted for acute on chronic renal failure due to dehydration
He certainly was treated for NSTEMI during admission.

1. Does the standard allow a coder to choose ARF as principal in this case, despite it being listed second by the doctor?
2. Are coders expected to refer all of these types cases back to the doctor to tell us what should be principal?
3. Although we code for reasons other than casemix funding, I feel that not taking admission circumstances into consideration and choosing the first listed diagnosis will result in DRG funding and report anomalies eg. Renal physicians will question why cardiac patients are listed on their reports.



Please advise on the general intent of this standard.

This query was originally published in June 2012 and previously retired on 30 June 2010. It was reinstated effective 1 July 2020 following a review as the advice is considered current.

In accordance with ACS 0001 Principal diagnosis under heading 'Two or more diagnoses that equally meet the definition for principal diagnosis', you are correct in that after reviewing the clinical notes if there is more than one diagnosis that can equally be principal diagnosis, the case should be referred to the clinician to indicate the principal diagnosis. If no further information is available, choose the first listed as principal diagnosis. However please note that in example 1 of ACS 0001, not all conditions listed on the front sheet meet principal diagnosis definition.

In response to your specific questions for the case cited:
1. No, the standard doesn't allow the coder to choose ARF as principal in this case. This is because there is evidence of both conditions being present on admission and after study both diagnoses were listed with NSTEMI as the first listed.

2. Only when there are two or more conditions equally meeting the criteria for principal diagnosis should the case be referred back to the clinician to to indicate which diagnosis best meets the principal diagnosis definition.

3. Codes should be assigned according to coding principles regardless of the DRG outcome. The unit the patient is admitted to does not determine principal diagnosis decision.