B19.21
BillableUnspecified viral hepatitis C with hepatic coma
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is B19.21 an HCC code?
No. B19.21 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for B19.21
For B19.21 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed B19.21 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
B19.21 is the ICD-10-CM diagnosis code for unspecified viral hepatitis c with hepatic coma. A viral infection of the liver caused by hepatitis C virus that has progressed to hepatic coma, a critical condition where the liver fails and affects brain function. B19.21 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering viral hepatitis (b15-b19).
B19.21 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.
Maps only to RxHCC 55 (Substance Use Disorder, Mild) with RAF 0.0. Despite the critical clinical severity of hepatic coma, this code does NOT map to any V28 or V24 community HCC. This highlights a gap where clinical severity does not align with risk adjustment capture for unspecified hepatitis C codes.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for B19.21 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code requires clear documentation of both hepatitis C and hepatic coma
- •Hepatic coma indicates fulminant hepatic failure; coordinate coding with critical care and encephalopathy codes
Clinical Significance
Unspecified viral hepatitis C with hepatic coma represents hepatitis C of unknown chronicity that has progressed to fulminant hepatic failure. This is a life-threatening condition requiring ICU care and potential liver transplant evaluation, yet it carries limited risk adjustment value due to its unspecified nature.
Documentation Requirements
- ✓Positive hepatitis C testing confirming viral etiology
- ✓Hepatic coma/hepatic encephalopathy documented with staging (West Haven criteria)
- ✓Liver function tests showing hepatic failure pattern
- ✓Coagulation studies demonstrating synthetic function failure
- ✓ICU admission documentation and treatment plan
Commonly Confused Codes
- •B17.11 (Acute hepatitis C with hepatic coma) — If the infection is confirmed acute, use the specific acute code
- •B19.20 (Unspecified viral hepatitis C without hepatic coma) — Same unspecified hepatitis C but without the hepatic coma component
- •K72.01 (Acute and subacute hepatic failure with coma) — Hepatic failure code not specifying viral etiology