ICD-10 G31.86
Billable / Specific HCC v28: 52Alexander disease
About ICD-10-CM G31.86
ICD-10-CM code G31.86 represents Alexander disease. This is a billable/specific code in the Nervous System chapter (block G31). The 2026 edition of ICD-10-CM G31.86 became effective on October 1, 2025.
Coding Tips for G31.86
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
G31.86 is a CMS-HCC v28 risk-adjustment code (category 52). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
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.
Medicare LCD Coverage for G31.86
Local Coverage Determinations (LCDs) from CMS MACs that list G31.86 as a covered diagnosis.
Showing top 10 of 427 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing G31.86.
2 Cigna
5 Medicare
CPT Codes Commonly Billed with G31.86
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- G0151 CMS LCD: Billing and Coding: Home Health Physical Therapy CMS LCD
- G0159 CMS LCD: Billing and Coding: Home Health Physical Therapy CMS LCD
- G2168 CMS LCD: Billing and Coding: Home Health Physical Therapy CMS LCD
- G0157 CMS LCD: Billing and Coding: Home Health Physical Therapy CMS LCD
- G0161 CMS LCD: Billing and Coding: Home Health Speech-Language Pathology CMS LCD
- G0153 CMS LCD: Billing and Coding: Home Health Speech-Language Pathology CMS LCD
- G0539 CMS LCD: Billing and Coding: Home Health Skilled Nursing Care-Teaching and Training: Alzheimer's Disease and Behavioral Disturbances CMS LCD
- G0540 CMS LCD: Billing and Coding: Home Health Skilled Nursing Care-Teaching and Training: Alzheimer's Disease and Behavioral Disturbances CMS LCD
Codes Adjacent To G31.86
Other codes in section G30-G32 (Other degenerative diseases of the nervous system).
ICD-10 G31.86, Billing FAQ
Is ICD-10 code G31.86 billable? +
Yes, G31.86 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does G31.86 affect Medicare Advantage HCC risk adjustment? +
Yes. G31.86 maps to CMS-HCC v28 category 52. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with G31.86? +
Procedures frequently paired with G31.86 include: G0151, G0159, G2168, G0157, G0161.
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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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