F05Delirium due to known physiological condition

F05 is the ICD-10-CM diagnosis code for delirium due to known physiological condition. It belongs to block F01-F09 (mental disorders due to known physiological conditions) and chapter 5 (mental, Behavioral and Neurodevelopmental disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Don't report F05 together with the conditions in its Excludes1 note: delirium NOS (R41.0).

The conditions in its Excludes2 note aren't part of F05, but may be coded alongside it if the patient has both: delirium tremens alcohol-induced or unspecified (F10.231, F10.921).

Code first the underlying physiological condition, such as: dementia (F03.9-).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 880 (Acute Adjustment Reaction and Psychosocial Dysfunction, relative weight 0.9306), in MDC 19 (Mental Diseases and Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 293.0 (delirium due to conditions classified elsewhere) and 293.1 (subacute delirium).