2027 ICD-10-CM Diagnosis Code E72.21Argininemia

ICD-10-CM Codes›E00–E89›E70-E88›E72

ICD-10-CM E72.21
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

E72.21 is a billable ICD-10-CM diagnosis code for argininemia. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 642. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 140 closely related codes. Coders also document this condition as arginase deficiency. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified nutritional and metabolic disorders.

E72.21 no longer risk-adjusts for Medicare Advantage: it mapped to HCC 23 under the retired CMS-HCC V24 model through payment year 2025 but maps to no category in the live V28 model. It still risk-adjusts in the PACE (CMS-HCC V22) category 23, ESRD (V21) category 23, ESRD (V24) category 23, and RxHCC Part D (V08) category 43 for payment year 2027.

Code Identity

ICD-10-CM Code
E72.21
Billable Status
Yes — Valid for Submission
Code Describes
Argininemia
Short Description
Argininemia
Same as the full description in the CMS dataset.
Parent Code
E72.2
Disorders of urea cycle metabolism

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE70-E88Metabolic disorders
CategoryE72Other disorders of amino-acid metabolism
This CodeE72.21Argininemia

Medicare Risk Adjustment (HCC)Billing

E72.21 no longer risk-adjusts for Medicare Advantage: it maps to no payment category in the live CMS-HCC V28 model, although it still risk-adjusts in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
Dropped in V28 see all codes that no longer risk-adjust
Prior Model (CMS-HCC V24)
HCC 23
V24 retired last contributed to a Medicare Advantage risk score in payment year 2025
Other CMS Models
PACE (CMS-HCC V22): HCC 23 · ESRD (V21): HCC 23 · ESRD (V24): HCC 23
ESRD V21 weights: 0.013 dialysis, 0.234–0.359 functioning graft · ESRD V24 weights: 0.036 dialysis, 0.217–0.390 functioning graft
Part D (RxHCC)
RxHCC 43 — Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Arginase deficiency
  • Deficiency of arginine deiminase

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to E72.21: its own notes plus those printed at E72.2, E72, block E70-E88, and Chapter 4. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From E72.2 Disorders of urea cycle metabolism applies to 5 codes
  • disorders of ornithine metabolism (E72.4)
From E72 Other disorders of amino-acid metabolism applies to 31 codes
  • disorders of:
  • aromatic amino-acid metabolism (E70.-)
  • branched-chain amino-acid metabolism (E71.0-E71.2)
  • fatty-acid metabolism (E71.3)
  • purine and pyrimidine metabolism (E79.-)
  • gout (M1A.-, M10.-)
From Block E70-E88 Metabolic disorders applies to 286 codes
  • androgen insensitivity syndrome (E34.5-)
  • congenital adrenal hyperplasia (E25.0)
  • hemolytic anemias attributable to enzyme disorders (D55.-)
  • Marfan syndrome (Q87.4-)
  • 5-alpha-reductase deficiency (E29.1)
From Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases applies to 973 codes
  • transitory endocrine and metabolic disorders specific to newborn (P70-P74)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block E70-E88 Metabolic disorders applies to 286 codes
  • Ehlers-Danlos syndromes (Q79.6-)

Notes

General instructions on how these codes are used.

From Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases applies to 973 codes
  • All neoplasms, whether functionally active or not, are classified in Chapter 2. Appropriate codes in this chapter (i.e. E05.8, E07.0, E16-E31, E34.-) may be used as additional codes to indicate either functional activity by neoplasms and ectopic endocrine tissue or hyperfunction and hypofunction of endocrine glands associated with neoplasms and other conditions classified elsewhere.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name E72.21, its category, or a range that includes it.

Excludes1 3

These codes carry an Excludes1 note naming E72.21: they are not reported together with it, unless the two conditions are unrelated.

  • R79 Other abnormal findings of blood chemistry
    specific findings indicating disorder of amino-acid metabolism (E70-E72) names E70-E72, which includes this code
  • R79.83 Abnormal findings of blood amino-acid level
    disorders of amino-acid metabolism (E70-E72) names E70-E72, which includes this code
  • Block R80-R82 Abnormal findings on examination of urine, without diagnosis
    specific findings indicating disorder of amino-acid metabolism (E70-E72) names E70-E72, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR END016
Other specified and unspecified nutritional and metabolic disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hyperargininemia

    a rare autosomal recessive disorder of the urea cycle. it is caused by a deficiency of the hepatic enzyme arginase. arginine is elevated in the blood and cerebrospinal fluid, and periodic hyperammonemia may occur. disease onset is usually in infancy or early childhood. clinical manifestations include seizures, microcephaly, progressive mental impairment, hypotonia, ataxia, spastic diplegia, and quadriparesis. (from hum genet 1993 mar;91(1):1-5; menkes, textbook of child neurology, 5th ed, p51)

Patient EducationClinical

Metabolic Disorders

Metabolism is the process your body uses to get or make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system break the food parts down into sugars and acids, your body's fuel.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert E72.21 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
270.6 Dis urea cycle metabol
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About E72.21Overview

What is the ICD-10 code for argininemia?

The ICD-10-CM code for argininemia is E72.21 (sometimes written as E7221). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is E72.21 (Disorders of urea cycle metabolism) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report argininemia on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does E72.21 group to?

When argininemia is the principal diagnosis on an inpatient stay, it groups to MS-DRG 642 (inborn and Other Disorders of Metabolism), which carries a relative weight of 1.3226. Higher weights mean higher Medicare reimbursement.

Is E72.21 a CC or MCC?

CMS lists E72.21 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 140 closely related codes in its exclusion list.

Can E72.21 be reported with E72.4?

Not as a rule. The Excludes1 note at E72.2, which applies to E72.21, lists "disorders of ornithine metabolism (E72.4)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

Does E72.21 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage. E72.21 mapped to HCC 23 in the retired CMS-HCC V24 model, which last determined payment in 2025, but it maps to no category in the live V28 model; see all codes that no longer risk-adjust. It still risk-adjusts in the PACE (CMS-HCC V22) category 23 (Other Significant Endocrine and Metabolic Disorders), ESRD (V21) category 23 (Other Significant Endocrine and Metabolic Disorders), ESRD (V24) category 23 (Other Significant Endocrine and Metabolic Disorders), and RxHCC Part D (V08) category 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders).