F43.0Acute stress reaction

F43.0 is the ICD-10-CM diagnosis code for acute stress reaction. It belongs to category F43 (reaction to severe stress, and adjustment disorders), block F40-F48 (anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders) and chapter 5 (mental, Behavioral and Neurodevelopmental disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within F43 (reaction to severe stress, and adjustment disorders), F43.0 is specifically for acute stress reaction. Related codes cover post-traumatic stress disorder (PTSD) (F43.1), adjustment disorders (F43.2), other reactions to severe stress (F43.8) and reaction to severe stress, unspecified (F43.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 880 (Acute Adjustment Reaction and Psychosocial Dysfunction, relative weight 0.9306), in MDC 19 (Mental Diseases and Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 308.9 (unspecified acute reaction to stress).