F43.9
Reaction to severe stress, unspecified
F43.9 (also written F439) is a billable ICD-10-CM diagnosis code for reaction to severe stress, unspecified. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 14 codes in category F43 (Reaction to severe stress, and adjustment disorders). The Alphabetic Index lists it under 6 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)
- 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-DRG | Description | Factor |
|---|---|---|
| 882 | Neuroses except depressive | 1.02 |
Includes
Further defines or gives examples of the content of the category.
Also from chapter/block level (1 note)
- disorders of psychological development
Inclusion terms
Conditions classified to this code.
- Trauma and stressor-related disorder, NOS
- Unspecified trauma and stressor-related disorder
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 6 entries