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Sudden Unexplained Death S018

Last amended 
17 May 2022
Current RMA Instruments
Reasonable Hypothesis SOP
45 of 2022
Balance of Probabilities SOP
46 of 2022
Changes from previous Instruments

SOP Bulletin 230

ICD Coding
  • ICD-9-CM Codes: 798.1, 798.2
  • ICD-10-AM Codes: R96
Brief description

This SOP is only used when there is no known underlying disease or injury which could account for the client’s death.

Confirming the diagnosis

This diagnosis is complex and is a diagnosis of exclusion. The contemporary medical documents should be sought, together with the death certificate, and if a coroner’s inquest or autopsy has been performed, these documents should also be sought.

The relevant medical specialist would be a pathologist (if there has been an autopsy) or the attending physician.

Additional diagnoses covered by SOP
  • Sudden unexpected death
Conditions excluded from SOP
  • Any death where an underlying disease or injury could have accounted for the death
  • Suicide - There is a separate SOP for suicide.
Clinical onset

The SOP definition requires death to have been within 24 hours of first symptoms, unless there has been medical intervention in the form of life support by mechanical devices (e.g. a ventilator).


The reference to the ‘QT interval’ in the SOP pertains to a measurement of the interval between the Q and the T waves in an electrocardiograph (ECG) tracing of the heart.

Physiological measurements around the time of death can be distorted. Any diagnoses of diabetes mellitus, hypertension or epilepsy need to have been made prior to the death episode.

It is common for chest trauma to occur during cardiopulmonary resuscitation. This is not a ‘blow to the chest immediately before the sudden unexplained death’ but chest trauma after the "onset" of sudden unexplained death as a form of treatment.