E31.22
BillableMultiple endocrine neoplasia [MEN] type IIA
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is E31.22 an HCC code?
Yes. E31.22 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 E31.22
For E31.22 to 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 E31.22 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
E31.22 is the ICD-10-CM diagnosis code for multiple endocrine neoplasia [men] type iia. Multiple endocrine neoplasia type IIA is an inherited genetic disorder where a person develops tumors in multiple endocrine glands, typically affecting the thyroid, parathyroid glands, and adrenal glands. This condition is caused by a mutation in the RET gene and runs in families. E31.22 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, E31.22 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, E31.22 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.
Always verify the specific type of MEN syndrome (IIA vs IIB vs other variants) in the documentation, as each has different clinical manifestations and coding requirements. Because E31.22 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 E31.22 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always verify the specific type of MEN syndrome (IIA vs IIB vs other variants) in the documentation, as each has different clinical manifestations and coding requirements
- •When coding MEN IIA, consider assigning additional codes for the specific endocrine tumors or conditions present (such as medullary thyroid carcinoma, hyperparathyroidism, or pheochromocytoma) to capture the complete clinical picture
Clinical Significance
Multiple endocrine neoplasia type IIA (Sipple syndrome) is an autosomal dominant condition caused by activating mutations in the RET proto-oncogene, predisposing to medullary thyroid carcinoma (nearly 100% penetrance), pheochromocytoma (50%), and primary hyperparathyroidism (20-30%). Early prophylactic thyroidectomy can be lifesaving when the genetic mutation is identified.
Documentation Requirements
- ✓Document RET proto-oncogene mutation testing results with specific codon affected, presence of medullary thyroid carcinoma (calcitonin levels, thyroid imaging), pheochromocytoma screening (catecholamines, metanephrines, adrenal imaging), parathyroid status, surgical history, and family screening results.