The principal diagnosis must be determined in accordance with the Australian Coding Standards. Each episode of admitted patient care must have a principal diagnosis and may have additional diagnoses. The diagnosis can include a disease, condition, injury, poisoning, sign, symptom, abnormal finding, complaint, or other factor influencing health status. As a minimum requirement the Principal diagnosis code must be a valid code from the current edition of ICD-10-AM. For episodes of admitted patient care, some diagnosis codes are too imprecise or inappropriate to be acceptable as a principal diagnosis and will group to an error DRG in the Australian Refined Diagnosis Related Groups. Diagnosis codes starting with a V, W, X or Y, describing the circumstances that cause an injury, rather than the nature of the injury, cannot be used as principal diagnosis. Diagnosis codes which are morphology codes cannot be used as principal diagnosis. | 
