ICD-10 G90.521
Billable / Specific CCComplex regional pain syndrome I of right lower limb
About ICD-10-CM G90.521
ICD-10-CM code G90.521 represents Complex regional pain syndrome I of right lower limb. This is a billable/specific code in the Nervous System chapter (block G90). The 2026 edition of ICD-10-CM G90.521 became effective on October 1, 2025.
Coding Tips for G90.521
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
G90.521 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Complex regional pain syndrome I of right lower limb. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for G90.521
Local Coverage Determinations (LCDs) from CMS MACs that list G90.521 as a covered diagnosis.
Showing top 10 of 655 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing G90.521.
3 Cigna
5 Medicare
CPT Codes Commonly Billed with G90.521
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 64596 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64598 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64570 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64597 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64569 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64581 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64590 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64555 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64595 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
- 64585 CMS LCD: Billing and Coding: Peripheral Nerve Stimulation CMS LCD
Convert G90.521 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| G90.521 | 33722 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To G90.521
Other codes in section G89-G99 (Other disorders of the nervous system).
ICD-10 G90.521, Billing FAQ
Is ICD-10 code G90.521 billable? +
Yes, G90.521 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Is G90.521 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with G90.521? +
Procedures frequently paired with G90.521 include: 64596, 64598, 64570, 64597, 64569.
What ICD-9 codes does G90.521 map to? +
Per CMS GEMs, G90.521 maps to ICD-9 codes: 33722. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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