2027 ICD-10-CM Diagnosis Code E70.21Tyrosinemia
ICD-10-CM Codes›E00–E89›E70-E88›E70
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
E70.21 is a billable ICD-10-CM diagnosis code for tyrosinemia. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified nutritional and metabolic disorders.
E70.21 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
Code Classification
Medicare Risk Adjustment (HCC)Billing
E70.21 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.
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.
- 4-Hydroxyphenylpyruvate dioxygenase deficiency
- Classical phenylketonuria
- Clinical manifestation of enzyme deficiency
- Deficiency of fumarylacetoacetase
- Fumarylacetoacetase deficiency, chronic type
- Hereditary hypertyrosinemia
- Hypertyrosinemia
- Persistent hyperphenylalaninemia
- Persistent hyperphenylalaninemia AND tyrosinemia
- Phenylketonuria
- Tyrosinemia type 1
- Tyrosinemia type 2
- Tyrosinemia type III
- Tyrosinosis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to E70.21: its own notes plus those printed at E70.2, block E70-E88, and Chapter 4. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Hypertyrosinemia
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- transitory tyrosinemia of newborn (P74.5)
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.
- Ehlers-Danlos syndromes (Q79.6-)
Notes
General instructions on how these codes are used.
- 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 E70.21, its category, or a range that includes it.
Excludes1 4
These codes carry an Excludes1 note naming E70.21: they are not reported together with it, unless the two conditions are unrelated.
- E72 Other disorders of amino-acid metabolismaromatic amino-acid metabolism (E70.-) names E70.-, which includes this code
- R79 Other abnormal findings of blood chemistry
- R79.83 Abnormal findings of blood amino-acid level
- Block R80-R82 Abnormal findings on examination of urine, without diagnosis
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Disorder (of) See Also: Disease;
Hypertyrosinemia E70.21
Tyrosinemia E70.21
Tyrosinosis E70.21
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Tyrosinemias
a group of disorders which have in common elevations of tyrosine in the blood and urine secondary to an enzyme deficiency. type i tyrosinemia features episodic weakness, self-mutilation, hepatic necrosis, renal tubular injury, and seizures and is caused by a deficiency of the enzyme fumarylacetoacetase. type ii tyrosinemia features intellectual disability, painful corneal ulcers, and keratoses of the palms and plantar surfaces and is caused by a deficiency of the enzyme tyrosine transaminase. type iii tyrosinemia features intellectual disability and is caused by a deficiency of the enzyme 4-hydroxyphenylpyruvate dioxygenase. (menkes, textbook of child neurology, 5th ed, pp42-3)
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 E70.21 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About E70.21Overview
What is the ICD-10 code for tyrosinemia?
The ICD-10-CM code for tyrosinemia is E70.21 (sometimes written as E7021). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is E70.21 (Disorders of tyrosine metabolism) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report tyrosinemia on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does E70.21 group to?
When tyrosinemia 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 E70.21 a CC or MCC?
CMS lists E70.21 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 E70.21 be reported with P74.5?
Not as a rule. The Excludes1 note at E70.2, which applies to E70.21, lists "transitory tyrosinemia of newborn (P74.5)". 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 E70.21 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage. E70.21 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).
