R40.4 ICD-10-CM Code: Transient alteration of awareness
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99) / Symptoms and signs involving cognition, perception, emotional state and behavior (R40-R46)
R40.4
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceTransient alteration of awareness
A brief, temporary loss of consciousness or awareness that resolves spontaneously.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for R40.4 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for R40.4 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for R40.4 in this effective period.
Excludes 1
Official- neonatal coma (P91.5)
- somnolence, stupor and coma in diabetes (E08-E13)
- somnolence, stupor and coma in hepatic failure (K72.-)
- somnolence, stupor and coma in hypoglycemia (nondiabetic) (E15)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for R40.4 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for R40.4 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for R40.4 in this effective period.
Buddy Documentation Tip
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 R40.4 an HCC code?
No. R40.4 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
R40.4 is the ICD-10-CM diagnosis code for transient alteration of awareness. A brief, temporary loss of consciousness or awareness that resolves spontaneously. R40.4 sits in the ICD-10-CM chapter for symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (r00-r99), within the section covering symptoms and signs involving cognition, perception, emotional state and behavior (r40-r46).
R40.4 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.
This code is used for transient episodes; if the altered awareness is prolonged or recurrent, investigate for seizures or syncope.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for R40.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code is used for transient episodes; if the altered awareness is prolonged or recurrent, investigate for seizures or syncope
- •Document the duration and any triggers or associated symptoms to help identify the underlying cause