E70.9
BillableDisorder of aromatic amino-acid metabolism, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is E70.9 an HCC code?
Yes. E70.9 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.
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 E70.9
For E70.9 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 E70.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
E70.9 is the ICD-10-CM diagnosis code for disorder of aromatic amino-acid metabolism, unspecified. This code describes a metabolic disorder affecting how the body processes certain amino acids (building blocks of proteins), but the specific type of disorder is not identified. These amino acids are important for producing neurotransmitters and other vital substances in the body. E70.9 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).
Under the older CMS-HCC V24 model, E70.9 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.230. 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.
Use this unspecified code only when the specific aromatic amino acid disorder (such as phenylketonuria, tyrosinemia, or alkaptonuria) cannot be determined from the medical record. Because E70.9 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 E70.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this unspecified code only when the specific aromatic amino acid disorder (such as phenylketonuria, tyrosinemia, or alkaptonuria) cannot be determined from the medical record
- •Query the provider if more specific diagnostic information is available, as this unspecified code may result in lower reimbursement and lacks clinical specificity
Clinical Significance
Unspecified disorder of aromatic amino-acid metabolism indicates a documented metabolic abnormality affecting aromatic amino acid processing where the specific type of disorder has not been identified. This is the least specific code in the E70 category and should prompt further diagnostic workup and provider query to determine the exact metabolic defect for appropriate management and genetic counseling.
Documentation Requirements
- ✓Documentation should include the laboratory evidence suggesting an aromatic amino acid metabolism abnormality, which specific amino acids are affected if known, current clinical presentation, and the plan for further diagnostic evaluation.
- ✓The provider should document why a more specific diagnosis cannot be established and what additional testing is planned.
- ✓Any clinical manifestations should be described.
Commonly Confused Codes
- •All specific E70 codes (E70.0 through E70.89) should be reviewed before assigning this unspecified code.
- •E71.x (Disorders of branched-chain amino-acid metabolism) involves different amino acids.
- •E72.x (Other disorders of amino-acid metabolism) covers non-aromatic amino acid disorders.
- •R79.89 (Other specified abnormal findings of blood chemistry) is a lab finding code, not a metabolic disorder diagnosis.