2027 ICD-10-CM Diagnosis Code E71.120Methylmalonic acidemia
ICD-10-CM Codes›E00–E89›E70-E88›E71
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
E71.120 is a billable ICD-10-CM diagnosis code for methylmalonic acidemia. 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.
E71.120 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
E71.120 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.
- Adenosylcobalamin and methylcobalamin synthesis defect
- Adenosylcobalamin synthesis defect
- Cobalamin A disease
- Cobalamin B disease
- Cobalamin C disease
- Cobalamin D disease
- Fatal infantile lactic acidosis with methylmalonic aciduria
- Homocystinuria
- Inherited methylmalonic acidemia AND homocystinuria
- Methylmalonic acidemia
- Methylmalonic acidemia due to methylmalonyl-coenzyme A epimerase deficiency
- Methylmalonic aciduria due to transcobalamin receptor defect
- Mitochondrial DNA depletion syndrome encephalomyopathic form
- Mitochondrial DNA depletion syndrome encephalomyopathic form with methylmalonic aciduria
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to E71.120: its own notes plus those printed at 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.
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 E71.120, its category, or a range that includes it.
Excludes1 4
These codes carry an Excludes1 note naming E71.120: they are not reported together with it, unless the two conditions are unrelated.
- E72 Other disorders of amino-acid metabolism
- 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.
Acidemia See Also: Acidosis; E87.20
methylmalonic E71.120
Disorder (of) See Also: Disease;
Methylmalonic acidemia E71.120
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Methylmalonic Acidemia
a genetically heterogenous inherited disorder characterized by abnormalities in the metabolism of lipids and proteins. signs and symptoms usually appear early in life and vary from mild to life threatening. they include vomiting, dehydration, hypotonia, developmental delays, hepatomegaly, lethargy, intellectual disabilities, and chronic kidney disease.
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 E71.120 to ICD-9-CMHistory
Code HistoryHistory
Questions About E71.120Overview
What is the ICD-10 code for methylmalonic acidemia?
The ICD-10-CM code for methylmalonic acidemia is E71.120 (sometimes written as E71120). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is E71.120 (Disorders of propionate metabolism) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report methylmalonic acidemia on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does E71.120 group to?
When methylmalonic acidemia 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 E71.120 a CC or MCC?
CMS lists E71.120 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 E71.120 be reported with a code from E34.5?
Not as a rule. The Excludes1 note at block E70-E88, which applies to E71.120, lists "androgen insensitivity syndrome (E34.5-)". 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 E71.120 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage. E71.120 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).
