What is ICD-10 code E72.29?

E72.29 is the ICD-10-CM diagnosis code for Other disorders of urea cycle metabolism. Other rare genetic disorders affecting the urea cycle that are not classified as arginosuccinic aciduria or citrullinemia. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E72.29 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E72.29 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. E72.29 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. E72.29 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for E72.29?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. E72.29 was a payment HCC under V24 (Other Significant Endocrine and Metabolic Disorders) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting E72.29?

Use this code for urea cycle disorders such as carbamoyl phosphate synthetase deficiency, ornithine transcarbamylase deficiency, or other variants Provide specific documentation of which urea cycle enzyme or process is affected Because E72.29 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

E72.29: Other disorders of urea cycle metabolism —

ICD-10-CM Code View

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Code lookupE72.29Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)

E72.29

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Other disorders of urea cycle metabolism

Other rare genetic disorders affecting the urea cycle that are not classified as arginosuccinic aciduria or citrullinemia.

Buddy Insight

Other disorders of urea cycle metabolism represent serious inborn errors that impair the body's ability to detoxify ammonia, a byproduct of protein metabolism.

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.230

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.0

RXHCC

Mapped

HCC 43

Other Significant Endocrine a...

RAF 0.0

Code Trumping

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Code Book Path

Official

E72Other disorders of amino-acid metabolism

E72.2Disorders of urea cycle metabolism

E72.29Other disorders of urea cycle metabolism

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for E72.29 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E72.29 in this effective period.

Related Child Codes

Official

E72.20Disorder of urea cycle metabolism, unspecified

E72.21Argininemia

E72.22Arginosuccinic aciduria

E72.23Citrullinemia

Includes

Official

ICD-10-CM does not list Includes notes for E72.29 in this effective period.

Excludes 1

Official

disorders of ornithine metabolism (E72.4)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E72.29 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E72.29 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E72.29 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Specific urea cycle enzyme deficiency identified (e.g., carbamoyl phosphate synthetase I deficiency, ornithine transcarbamylase deficiency, N-acetylglutamate synthase deficiency)

Laboratory confirmation such as plasma amino acid levels, urine orotic acid, or genetic testing results

Current treatment plan including dietary protein restrictions, nitrogen scavenger medications, or supplements

Monitoring of ammonia levels and neurological status

MEAT Support

HCC Buddy guidance

Specific urea cycle enzyme deficiency identified (e.g., carbamoyl phosphate synthetase I deficiency, ornithine transcarbamylase deficiency, N-acetylglutamate synthase deficiency)

Laboratory confirmation such as plasma amino acid levels, urine orotic acid, or genetic testing results

Current treatment plan including dietary protein restrictions, nitrogen scavenger medications, or supplements

Monitoring of ammonia levels and neurological status

Audit Caution

HCC Buddy guidance

Failing to distinguish between specific urea cycle enzyme deficiencies that have their own codes (E72.21-E72.23) versus using this residual code

Not querying the provider for the specific enzyme deficiency when genetic testing results are available in the chart

Confusing urea cycle disorders with general amino acid metabolism disorders (E72.89)

Missing the opportunity to code associated complications such as hyperammonemic encephalopathy separately

Common Mistakes

HCC Buddy guidance

E72.20 — Disorder of urea cycle metabolism, unspecified: use when specific enzyme defect is not documented

E72.21 — Argininemia: specific urea cycle defect involving arginase deficiency

E72.22 — Arginosuccinic aciduria: specific deficiency of argininosuccinate lyase

E72.23 — Citrullinemia: specific deficiency of argininosuccinate synthetase

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 E72.29 an HCC code?

Yes. E72.29 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.

HCC Category Mapping

V24HCC 23, Other Significant Endocrine and Metabolic Disorders

0.230

ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders

0.000

RxHCCHCC 43, Other Significant Endocrine and Metabolic Disorders

0.000

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 E72.29

For E72.29to 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 E72.29 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E72.29 is the ICD-10-CM diagnosis code for other disorders of urea cycle metabolism. Other rare genetic disorders affecting the urea cycle that are not classified as arginosuccinic aciduria or citrullinemia. E72.29 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, E72.29 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 code for urea cycle disorders such as carbamoyl phosphate synthetase deficiency, ornithine transcarbamylase deficiency, or other variants. Because E72.29 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 E72.29 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code for urea cycle disorders such as carbamoyl phosphate synthetase deficiency, ornithine transcarbamylase deficiency, or other variants
•Provide specific documentation of which urea cycle enzyme or process is affected

Clinical Significance

Other disorders of urea cycle metabolism represent serious inborn errors that impair the body's ability to detoxify ammonia, a byproduct of protein metabolism. Hyperammonemia from these disorders can cause irreversible brain damage and is life-threatening if not managed. Accurate capture is critical for risk adjustment as these patients require lifelong dietary management and monitoring.

Documentation Requirements

✓Specific urea cycle enzyme deficiency identified (e.g., carbamoyl phosphate synthetase I deficiency, ornithine transcarbamylase deficiency, N-acetylglutamate synthase deficiency)
✓Laboratory confirmation such as plasma amino acid levels, urine orotic acid, or genetic testing results
✓Current treatment plan including dietary protein restrictions, nitrogen scavenger medications, or supplements
✓Monitoring of ammonia levels and neurological status
✓Clinical manifestations documented (e.g., hyperammonemia episodes, developmental delays, encephalopathy)

Commonly Confused Codes

•E72.20: Disorder of urea cycle metabolism, unspecified: use when specific enzyme defect is not documented
•E72.21: Argininemia: specific urea cycle defect involving arginase deficiency
•E72.22: Arginosuccinic aciduria: specific deficiency of argininosuccinate lyase
•E72.23: Citrullinemia: specific deficiency of argininosuccinate synthetase
•E72.4: Disorders of ornithine metabolism: ornithine-related but distinct from urea cycle enzyme deficiencies