ICD-10 E31.1
Billable / Specific HCC v28: 23Polyglandular hyperfunction
About ICD-10-CM E31.1
ICD-10-CM code E31.1 represents Polyglandular hyperfunction. This is a billable/specific code in the Endocrine, Nutritional, and Metabolic chapter (block E31). The 2026 edition of ICD-10-CM E31.1 became effective on October 1, 2025.
Coding Tips for E31.1
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
E31.1 is a CMS-HCC v28 risk-adjustment code (category 23). 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.
Type 1 Excludes
Pure excludes, these codes can never be coded together with E31.1. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- multiple endocrine adenomatosis (E31.2-)
- multiple endocrine neoplasia (E31.2-)
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 E31.1
Local Coverage Determinations (LCDs) from CMS MACs that list E31.1 as a covered diagnosis.
Showing top 10 of 28 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing E31.1.
1 Medicare
CPT Codes Commonly Billed with E31.1
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Convert E31.1 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 |
|---|---|---|
| E31.1 | 2588 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To E31.1
Other codes in section E20-E35 (Disorders of other endocrine glands).
ICD-10 E31.1, Billing FAQ
Is ICD-10 code E31.1 billable? +
Yes, E31.1 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What codes are Type 1 Excludes for E31.1? +
Type 1 Excludes (never code together with E31.1): multiple endocrine adenomatosis (E31.2-); multiple endocrine neoplasia (E31.2-)
Does E31.1 affect Medicare Advantage HCC risk adjustment? +
Yes. E31.1 maps to CMS-HCC v28 category 23. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What ICD-9 codes does E31.1 map to? +
Per CMS GEMs, E31.1 maps to ICD-9 codes: 2588. Useful for legacy data review and historical claim analysis.
Get the full PayerReady toolkit
Free access to CPT/ICD-10 lookup, denial appeals, fee comparator, and claim auditing with credentialing enrollment.
Start free →Run this code through our claim audit tool
Check NCCI bundling, MUE limits, and modifier logic before submission.
Try the auditor →Did this page help?
Quick signal so we know what to improve.
If you want a code reference page that doesn't exist yet, email coding@payerready.com.
Tell us what's missing or wrong: coding@payerready.com. We respond within 5 business days.
Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
Powered by 11K CPT · 98K ICD-10 · 860K MPFS rates · 4.5M NCCI edits · 9.5M NPIs. Our data methodology · About our coding team