Question 1

What is ICD-10 code G90.522?

Accepted Answer

G90.522 is the ICD-10-CM diagnosis code for complex regional pain syndrome i of left lower limb. A chronic pain condition affecting the left leg or foot after injury, with swelling, skin color and temperature changes, and pain that seems worse than expected from the original injury. G90.522 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).

G90.522 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.

Confirm left lower limb involvement is clearly documented before coding.

Question 2

Is G90.522 an HCC code?

Accepted Answer

No. G90.522 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 G90.522 billable?

Accepted Answer

Yes. G90.522 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. G90.522 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 G90.522?

Accepted Answer

G90.522 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 G90.522 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 G90.522?

Accepted Answer

Confirm left lower limb involvement is clearly documented before coding Include the precipitating injury code when identified and documented

HCC Buddy Code Card

G90.522

Is G90.522 an HCC code?

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Open G90.522 in the Interactive Encoder

G90.522 ICD-10-CM Code: Complex regional pain syndrome I of left lower limb

HCC Buddy Code Card

G90.522

Is G90.522 an HCC code?

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Open G90.522 in the Interactive Encoder