A08.11 ICD-10-CM Code: Acute gastroenteropathy due to Norwalk agent
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 / Certain infectious and parasitic diseases (A00-B99) / Intestinal infectious diseases (A00-A09)
A08.11
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAcute gastroenteropathy due to Norwalk agent
This is a stomach and intestinal infection caused by the Norwalk virus, which causes sudden onset of nausea, vomiting, diarrhea, and abdominal discomfort. It typically resolves on its own within a few days but can cause significant dehydration.
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
Official- Acute gastroenteropathy due to Norovirus
- Acute gastroenteropathy due to Norwalk-like agent
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A08.11 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for A08.11 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A08.11 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A08.11 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A08.11 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A08.11 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 A08.11 an HCC code?
No. A08.11 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
Get the V28 RAF + MEAT cheat sheet
One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.
Free PDF. No card. Unsubscribe anytime.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A08.11 is the ICD-10-CM diagnosis code for acute gastroenteropathy due to norwalk agent. This is a stomach and intestinal infection caused by the Norwalk virus, which causes sudden onset of nausea, vomiting, diarrhea, and abdominal discomfort. It typically resolves on its own within a few days but can cause significant dehydration. A08.11 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering intestinal infectious diseases (a00-a09).
A08.11 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.
Verify documentation specifically mentions Norwalk agent or norovirus to distinguish from other viral gastroenteritis causes (A08.19).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A08.11 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.