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F43.0 ICD-10-CM Code: Acute stress reaction

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FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (F40-F48)

F43.0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Acute stress reaction

A temporary emotional and physical reaction that occurs immediately after experiencing or witnessing a traumatic or extremely stressful event, typically lasting from hours to a few days.

CMS-HCC V28

0

0

RAF 0

CMS-HCC V24

0

0

RAF 0

ACA/HHS

0

0

RAF 0

ESRD/PACE

0

0

RAF 0

RXHCC

0

0

RAF 0

Code Trumping

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Code Book Path

Official
F43Reaction to severe stress, and adjustment disorders
F43.0Acute stress reaction

Inclusion Terms

Official
  • Acute crisis reaction
  • Acute reaction to stress
  • Combat and operational stress reaction
  • Combat fatigue
  • Crisis state

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for F43.0 in this effective period.

Related Child Codes

Official
F43.1Post-traumatic stress disorder (PTSD)
F43.2Adjustment disorders
F43.8Other reactions to severe stress
F43.9Reaction to severe stress, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for F43.0 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for F43.0 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for F43.0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for F43.0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for F43.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Document the specific stressor or traumatic event that triggered the acute stress reaction
Distinguish from PTSD by noting the acute onset and short duration (usually resolves within days)

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is F43.0 an HCC code?

No. F43.0 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

Coder workflow notes

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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).

What This Code Means

F43.0 is the ICD-10-CM diagnosis code for acute stress reaction. A temporary emotional and physical reaction that occurs immediately after experiencing or witnessing a traumatic or extremely stressful event, typically lasting from hours to a few days. F43.0 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (f40-f48).

F43.0 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Document the specific stressor or traumatic event that triggered the acute stress reaction.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for F43.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • Document the specific stressor or traumatic event that triggered the acute stress reaction
  • Distinguish from PTSD by noting the acute onset and short duration (usually resolves within days)

Child Codes

Code Hierarchy

Work F43.0 in HCC Buddy

Open F43.0 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 14 days to try everything.