HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Disorders of other endocrine glands (E20-E35)
E31.0
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAutoimmune polyglandular failure
A condition where the immune system attacks multiple glands in the body, causing them to fail and stop producing necessary hormones.
Buddy Insight
Autoimmune polyglandular failure (autoimmune polyendocrine syndrome) involves immune-mediated destruction of multiple endocrine glands simultaneously, most commonly affecting adrenal, thyroid, and pancreatic islet cells.
CMS-HCC V28
MappedHCC 51
RAF 0.233
CMS-HCC V24
MappedHCC 23
RAF 0.230
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 23
RAF 0.0
RXHCC
MappedHCC 43
RAF 0.0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
Official- Schmidt's syndrome
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for E31.0 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E31.0 in this effective period.
Excludes 1
Official- ataxia telangiectasia [Louis-Bar] (G11.3)
- dystrophia myotonica [Steinert] (G71.11)
- pseudohypoparathyroidism (E20.1)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for E31.0 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for E31.0 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for E31.0 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is E31.0 an HCC code?
Yes. E31.0 maps to Other Significant Endocrine and Metabolic Disorders under the CMS-HCC V28 risk adjustment model (and Other Significant Endocrine and Metabolic Disorders under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for E31.0
For E31.0to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed E31.0 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
E31.0 is the ICD-10-CM diagnosis code for autoimmune polyglandular failure. A condition where the immune system attacks multiple glands in the body, causing them to fail and stop producing necessary hormones. E31.0 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering disorders of other endocrine glands (e20-e35).
Under the CMS-HCC V28 risk adjustment model, E31.0 maps to Other Significant Endocrine and Metabolic Disorders (HCC 51) with a community, non-dual, aged base RAF weight of 0.233. Under the older V24 model, E31.0 mapped to the same category but with a base RAF weight of 0.230 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Document which specific glands are affected (thyroid, adrenal, parathyroid, etc.) for more specific coding if available. Because E31.0 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E31.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document which specific glands are affected (thyroid, adrenal, parathyroid, etc.) for more specific coding if available
- •This is often associated with Addison's disease and hypothyroidism; review documentation for additional diagnoses to code
Clinical Significance
Autoimmune polyglandular failure (autoimmune polyendocrine syndrome) involves immune-mediated destruction of multiple endocrine glands simultaneously, most commonly affecting adrenal, thyroid, and pancreatic islet cells. Type I (autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy) presents in childhood, while Type II (Schmidt syndrome) is more common and presents in adulthood with Addison disease, autoimmune thyroid disease, and type 1 diabetes mellitus.
Documentation Requirements
- ✓Document which specific glands are affected, autoimmune antibody panel results, individual hormone deficiencies and replacement therapies, genetic testing if applicable (AIRE gene for Type I), associated non-endocrine autoimmune conditions, and comprehensive management plan.