F43.9 — Reaction to severe stress, unspecified
F43.9 is a billable, specific ICD-10-CM code for reaction to severe stress, unspecified. It is valid for submission on a claim.
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- Trauma and stressor-related disorder, NOS
- Unspecified trauma and stressor-related disorder
Risk adjustment
F43.9 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
F43.9 is named in 5 Medicare coverage policies — 4 listing it as supporting medical necessity, and 1 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A52434Health and Behavior Assessment/Intervention – Medical Policy Articlenot covered
- A56645Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing
- A57130Billing and Coding: Psychiatric Codes
- A57480Billing and Coding: Psychiatry and Psychology Services
How F43.9 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to F43.9.
- Stress
- Disorder›stress
- Disorder›trauma and stressor-related NOS
- Reaction›stress(severe)
- Stress›reaction
- Disorder›trauma and stressor-related NOS›unspecified
Related codes at this level
Codes that share F43. If F43.9 is not quite right, the correct code is usually one of these.
Questions about F43.9
- Is F43.9 a billable ICD-10-CM code?
- Yes. F43.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does F43.9 sit in the tabular list?
- Mental, Behavioral and Neurodevelopmental disorders (F01-F99), in the block Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (F40-F48).