2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Symptoms, Signs, And Ill-Defined Conditions 780-799 > Ill-Defined And Unknown Causes Of Morbidity And Mortality 797-799 > ICD-9-CM Diagnosis 798 Sudden death cause unknown 798 is a non-specific code that cannot be used to specify a diagnosis ICD-9-CM Diagnosis 798.0 Sudden infant death syndrome The abrupt and unexplained death of an apparently healthy infant under one year of age, remaining unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history. (Pediatr Pathol 1991 Sep-Oct;11 798.0 is a specific code that can be used to specify a diagnosis 798.0 contains 10 index entries ICD-9-CM Diagnosis 798.1 Instantaneous death 798.1 is a specific code that can be used to specify a diagnosis 798.1 contains 7 index entries ICD-9-CM Diagnosis 798.2 Death occurring in less than 24 hours from onset of symptoms not otherwise explained 798.2 is a specific code that can be used to specify a diagnosis 798.2 contains 3 index entries ICD-9-CM Diagnosis 798.9 Unattended death 798.9 is a specific code that can be used to specify a diagnosis 798.9 contains 3 index entries