E70.9 ICD-10-CM Code: Disorder of aromatic amino-acid metabolism, unspecified
E70.9 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools
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FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)
E70.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceDisorder 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.
Buddy Insight
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.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
Context neededHCC 028
Coefficient needs member context
ESRD/PACE
Context neededHCC 23
Coefficient needs member context
RXHCC
MappedHCC 43
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for E70.9. Check the code and parent instructions in the Code Book.
Excludes 2
Official- Ehlers-Danlos syndromes (Q79.6-)Inherited from E70-E88
Related Codes
Includes
OfficialNo Includes notes are included in this display for E70.9. Check the code and parent instructions in the Code Book.
Excludes 1
Official- transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E70-E88
- androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88
- congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88
- hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88
- Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88
- 5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88
Code First
OfficialNo Code First sequencing instructions are included in this display for E70.9. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for E70.9. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for E70.9. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is E70.9 an HCC code?
E70.9 has no mapping under the current CMS-HCC V28 community payment model. E70.9 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E70.9 also appears in the HHS-HCC commercial risk model (HCC 028 (HHS-HCC 028 child, RAF varies by metal level)), where the result depends on member context and is not a Medicare Advantage payment mapping.
- Code
- E70.9
- Description
- Disorder of aromatic amino-acid metabolism, unspecified
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work E70.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for E70.9
For E70.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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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).
E70.9 has no mapping under the current CMS-HCC V28 community payment model. E70.9 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E70.9 also appears in the HHS-HCC commercial risk model (HCC 028 (HHS-HCC 028 child, RAF varies by metal level)), where the result depends on member context and is not a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.
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.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, 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.