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E72.23 ICD-10-CM Code: Citrullinemia

E72.23 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

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

E72.23

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

Citrullinemia

A rare genetic disorder where the body cannot properly process the amino acid citrulline, leading to its accumulation and elevated ammonia levels.

Buddy the Bee presenting code insight

Buddy Insight

Citrullinemia encompasses two distinct genetic disorders: type I (classic, due to argininosuccinate synthetase deficiency) presenting with severe neonatal hyperammonemia, and type II (due to citrin deficiency) presenting with adult-onset neuropsychiatric symptoms and fatty liver.

CMS-HCC V28

N/A

—

Not mapped

CMS-HCC V24

HCC 23

RAF 0.194

ACA/HHS

HCC 28

Varies by metal level

ESRD/PACE

HCC 23

RAF 0.036

RXHCC

HCC 43

RAF 0.063

Code Book Path

Official
E72Other disorders of amino-acid metabolism
E72.2Disorders of urea cycle metabolism
E72.23Citrullinemia

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for E72.23 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E72.23 in this effective period.

Related Child Codes

Official
E72.20Disorder of urea cycle metabolism, unspecified
E72.21Argininemia
E72.22Arginosuccinic aciduria
E72.29Other disorders of urea cycle metabolism

Includes

Official

ICD-10-CM does not list Includes notes for E72.23 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 E72.23 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E72.23 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E72.23 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Document whether type I or type II citrullinemia, plasma citrulline levels (markedly elevated in type I), ammonia levels, genetic testing for ASS1 (type I) or SLC25A13 (type II) mutations, clinical presentation and severity, and management plan including dietary restrictions, nitrogen scavenger therapy, or liver transplant consideration.

MEAT Support

HCC Buddy guidance
Document whether type I or type II citrullinemia, plasma citrulline levels (markedly elevated in type I), ammonia levels, genetic testing for ASS1 (type I) or SLC25A13 (type II) mutations, clinical presentation and severity, and management plan including dietary restrictions, nitrogen scavenger therapy, or liver transplant consideration.

Audit Caution

HCC Buddy guidance
Type I and type II citrullinemia have fundamentally different genetics, clinical presentations, and treatments despite sharing the same ICD-10 code.
Document the specific type clearly.
Type II may be missed if the hepatic and neuropsychiatric presentation is not linked to the underlying metabolic defect.

Common Mistakes

HCC Buddy guidance
E72.22 (Arginosuccinic aciduria) which involves the next enzyme in the urea cycle
E72.21 (Argininemia) for arginase deficiency
E72.20 (Disorder of urea cycle metabolism, unspecified) which lacks specificity
K76.0 (Fatty liver, not elsewhere classified) when type II citrullinemia is not recognized as the cause.

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 E72.23 an HCC code?

Yes. E72.23 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.

Code
E72.23
Description
Citrullinemia
HCC (V28)
No CMS-HCC V28 mapping
RAF
—
Billable
Yes
Payment year
2026

HCC Category Mapping

V24HCC 23, Other Significant Endocrine and Metabolic Disorders
0.194
ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders
0.036
RxHCCHCC 43, Other Significant Endocrine and Metabolic Disorders
0.063

Each model's RAF is its CMS base weight for that model's standard population, so 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 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.

Work E72.23 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for E72.23

For E72.23 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 E72.23 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E72.23 is the ICD-10-CM diagnosis code for citrullinemia. A rare genetic disorder where the body cannot properly process the amino acid citrulline, leading to its accumulation and elevated ammonia levels. E72.23 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, E72.23 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.194. 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.

Distinguish between Type I (classic) and Type II citrullinemia, as they have different genetic causes and treatment approaches. Because E72.23 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 E72.23 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Distinguish between Type I (classic) and Type II citrullinemia, as they have different genetic causes and treatment approaches
  • •Document ammonia levels and any hyperammonemic episodes in the medical record

Clinical Significance

Citrullinemia encompasses two distinct genetic disorders: type I (classic, due to argininosuccinate synthetase deficiency) presenting with severe neonatal hyperammonemia, and type II (due to citrin deficiency) presenting with adult-onset neuropsychiatric symptoms and fatty liver. Type I is one of the most severe urea cycle disorders, with neonatal presentation often requiring emergency ammonia-lowering treatment. Type II has a distinctive predilection for individuals of East Asian descent.

Documentation Requirements

  • ✓Document whether type I or type II citrullinemia, plasma citrulline levels (markedly elevated in type I), ammonia levels, genetic testing for ASS1 (type I) or SLC25A13 (type II) mutations, clinical presentation and severity, and management plan including dietary restrictions, nitrogen scavenger therapy, or liver transplant consideration.

Commonly Confused Codes

  • •E72.22 (Arginosuccinic aciduria) which involves the next enzyme in the urea cycle
  • •E72.21 (Argininemia) for arginase deficiency
  • •E72.20 (Disorder of urea cycle metabolism, unspecified) which lacks specificity
  • •K76.0 (Fatty liver, not elsewhere classified) when type II citrullinemia is not recognized as the cause.

Child Codes

E72.20Disorder of urea cycle metabolism, unspecified
E72.21Argininemia
E72.22Arginosuccinic aciduria
E72.23Citrullinemia
E72.29Other disorders of urea cycle metabolism

Code Hierarchy

└E72Other disorders of amino-acid metabolism└E72.2Disorders of urea cycle metabolism└E72.23Citrullinemia
└E72.23Citrullinemia

Because E72.23 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.

Work E72.23 in HCC Buddy

Open E72.23 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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