FAQs - What is casemix and the clinical coder's role?

Casemix is a general term which describes any system which aggregates information about patients and associated procedures into groups based on the type and mix of the patients treated.

The role of the clinical coder is to correctly identify and translate the narrative descriptions of diseases, injuries and procedures contained in medical records into alphanumeric codes.These codes are used for several purposes including the provision of information for health service planning.

In Australia clinical coders use the coding classification system ICD-10-AM, ACHI and ACS to group inpatient separations into clinically homogeneous groups that are expected to consume similar amounts of resources. These groups are known as AR-DRGs.
(Australian Refined Diagnosis Related Group)

A hospital’s casemix is ascertained from inpatient stay data collected by the clinical coder from the patient record and manually coded into electronic systems. As well as demographic information the data collected on each episode of care includes detailed information on the diagnoses and procedures relevant to the patient during the inpatient treatment.

Each AR-DRG is allocated a cost weight which includes inputs for clinician attendance, pharmacy, radiology, allied health and other hospital costs and an average length of stay. The outputs of each hospital are then used in conjunction with fixed components such as clinical education and research grants and adjusted for population changes to calculate the level of funding.