Alphabetic Index FY2027

F40.9

Phobic anxiety disorder, unspecified

FY2027Chapter 5: Mental, Behavioral and Neurodevelopmental disorders/F40–F48 Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders

BillableComplete code, valid to report
Care settingsIPF Primary · MS-DRG 882

F40.9 (also written F409) is a billable ICD-10-CM diagnosis code for phobic anxiety disorder, unspecified. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 23 codes in category F40 (Phobic anxiety disorders). The Alphabetic Index lists it under 10 entries. Its coding notes include 1 Excludes2 entry.

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (1 note)
Inherited from Chapter 5 Mental, Behavioral and Neurodevelopmental disorders
  • symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

IPF Primary

IPF MS-DRG adjustment. A principal diagnosis of this code groups to this MS-DRG:

MS-DRGDescriptionFactor
882Neuroses except depressive1.02
A principal diagnosis that groups to none of the 19 designated MS-DRGs gets no MS-DRG adjustment. Otherwise the claim still receives the federal per diem base rate and the other adjustments.

Source: CMS IPF PPS FY 2027 final rule (CMS-1847-F), Addendum A; code lists from the CMS MS-DRG Definitions Manual v44; effective for discharges on or after October 1, 2026

Includes

Further defines or gives examples of the content of the category.

Also from chapter/block level (1 note)
Inherited from Chapter 5 Mental, Behavioral and Neurodevelopmental disorders
  • disorders of psychological development

Inclusion terms

Conditions classified to this code.

This code
  • Phobia NOS
  • Phobic state NOS

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 10 entries