Question 1

What is ICD-10 code G08?

Accepted Answer

G08 is the ICD-10-CM diagnosis code for intracranial and intraspinal phlebitis and thrombophlebitis. Inflammation and blood clot formation in the veins of the brain or spinal cord. G08 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering inflammatory diseases of the central nervous system (g00-g09).

G08 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.

Document whether this is phlebitis (vein inflammation) or thrombophlebitis (vein inflammation with clot).

Question 2

Is G08 an HCC code?

Accepted Answer

No. G08 is a billable ICD-10-CM code but does not map to any payment HCC category under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can still be reported on Medicare Advantage encounter data submissions, but it does not contribute to the beneficiary's Risk Adjustment Factor (RAF) score and therefore does not affect the risk-adjusted capitation payment to the plan. V28 reached 100% phase-in for payment year 2026.

Question 3

Is G08 billable?

Accepted Answer

Yes. G08 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. G08 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Question 4

What is the V28 vs V24 difference for G08?

Accepted Answer

G08 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards G08 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

Question 5

What should coders know when reporting G08?

Accepted Answer

Document whether this is phlebitis (vein inflammation) or thrombophlebitis (vein inflammation with clot) Identify the underlying cause (infection, trauma, malignancy) as this guides treatment decisions

G08

Is G08 an HCC code?

What This Code Means

Coding Tips

Excludes 1 — Do NOT code together

Excludes 2 — Not included here, may code separately

Code Hierarchy

Open G08 in the Interactive Encoder