G98.8
BillableOther disorders of nervous system
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G98.8 an HCC code?
No. G98.8 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
G98.8 is the ICD-10-CM diagnosis code for other disorders of nervous system. This code is used for nervous system disorders that don't fit into other specific ICD-10-CM categories. It's a catch-all code for rare or unusual neurological conditions that have been documented by the physician but lack a more precise diagnostic code. G98.8 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering other disorders of the nervous system (g89-g99).
G98.8 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.
Always attempt to use a more specific nervous system disorder code first; G98.8 should only be used when the condition truly cannot be classified elsewhere.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G98.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always attempt to use a more specific nervous system disorder code first; G98.8 should only be used when the condition truly cannot be classified elsewhere
- •Include detailed documentation from the physician describing the specific nervous system disorder to support medical necessity and justify the use of this unspecified code