ICD-10 F05
Billable / Specific CCDelirium due to known physiological condition
About ICD-10-CM F05
ICD-10-CM code F05 represents Delirium due to known physiological condition. This is a billable/specific code in the Mental, Behavioral, and Neurodevelopmental chapter (block F05). The 2026 edition of ICD-10-CM F05 became effective on October 1, 2025.
Coding Tips for F05
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
F05 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under F05. Per CMS ICD-10-CM Tabular 2026.
- Acute or subacute brain syndrome
- Acute or subacute confusional state (nonalcoholic)
- Acute or subacute infective psychosis
- Acute or subacute organic reaction
- Acute or subacute psycho-organic syndrome
- Delirium of mixed etiology
- Delirium superimposed on dementia
- Sundowning
Type 1 Excludes
Pure excludes, these codes can never be coded together with F05. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- delirium NOS (R41.0)
Type 2 Excludes
Not included here, the excluded code is not part of F05, but a patient may have both conditions at the same time. Both codes may be coded together when applicable.
- delirium tremens alcohol-induced or unspecified (F10.231, F10.921)
Coding Notes
Code First
- the underlying physiological condition, such as:
- dementia (F03.9-)
Inpatient DRG Impact, CC
code Delirium due to known physiological condition. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for F05
Local Coverage Determinations (LCDs) from CMS MACs that list F05 as a covered diagnosis.
Showing top 10 of 354 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing F05.
1 Cigna
5 Medicare
CPT Codes Commonly Billed with F05
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- G0252 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- 78608 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- A9597 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- A9601 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- G0235 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- 78609 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- A9552 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- G0219 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- A9598 CMS LCD: Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions CMS LCD
- 83970 CMS LCD: Billing and Coding: Parathormone (Parathyroid Hormone) CMS LCD
Convert F05 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| F05 | 2930 | 10000 |
| F05 | 2931 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To F05
Other codes in section F01-F09 (Mental disorders due to known physiological conditions).
ICD-10 F05, Billing FAQ
Is ICD-10 code F05 billable? +
Yes, F05 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to F05? +
ICD-10 F05 includes: Acute or subacute brain syndrome; Acute or subacute confusional state (nonalcoholic); Acute or subacute infective psychosis, and 5 more clinical synonyms.
What codes are Type 1 Excludes for F05? +
Type 1 Excludes (never code together with F05): delirium NOS (R41.0)
What codes are Type 2 Excludes for F05? +
Type 2 Excludes (may be coded together when both conditions exist): delirium tremens alcohol-induced or unspecified (F10.231, F10.921)
Is F05 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with F05? +
Procedures frequently paired with F05 include: G0252, 78608, A9597, A9601, G0235.
What ICD-9 codes does F05 map to? +
Per CMS GEMs, F05 maps to ICD-9 codes: 2930, 2931. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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