FY2027 ICD-10-CM reference
E88.4: Mitochondrial metabolism disorders
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Mitochondrial metabolism disorders. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Nonbillable heading. Verified against the official FY2027 order file.
More specific FY2027 codes
- E88.40: Mitochondrial metabolism disorder, unspecifiedBillable code
- E88.41: MELAS syndromeBillable code
- E88.42: MERRF syndromeBillable code
- E88.43: Disorders of mitochondrial tRNA synthetasesBillable code
- E88.49: Other mitochondrial metabolism disordersBillable code
FY2027 Tabular instructions
Instructions below include applicable chapter, section and parent-code notes. Each note identifies where it appears in the official source.
Instructional note
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: E00-E89 (chapter, inherited).
Excludes1
transitory endocrine and metabolic disorders specific to newborn (P70-P74)
Source: E00-E89 (chapter, inherited).
Excludes1
androgen insensitivity syndrome (E34.5-)
Source: E70-E88 (section, inherited).
Excludes1
congenital adrenal hyperplasia (E25.0)
Source: E70-E88 (section, inherited).
Excludes1
hemolytic anemias attributable to enzyme disorders (D55.-)
Source: E70-E88 (section, inherited).
Excludes1
Marfan syndrome (Q87.4-)
Source: E70-E88 (section, inherited).
Excludes1
5-alpha-reductase deficiency (E29.1)
Source: E70-E88 (section, inherited).
Excludes2
Ehlers-Danlos syndromes (Q79.6-)
Source: E70-E88 (section, inherited).
Instructional note
codes for associated conditions
Source: E88 (category, inherited).
Excludes1
histiocytosis X (chronic) (C96.6)
Source: E88 (category, inherited).
Excludes1
disorders of pyruvate metabolism (E74.4)
Source: E88.4 (self, direct).
Excludes1
Kearns-Sayre syndrome (H49.81)
Source: E88.4 (self, direct).
Excludes1
Leber's disease (H47.22)
Source: E88.4 (self, direct).
Excludes1
Leigh's encephalopathy (G31.82)
Source: E88.4 (self, direct).
Excludes1
Mitochondrial myopathy, NEC (G71.3)
Source: E88.4 (self, direct).
Excludes1
Reye's syndrome (G93.7)
Source: E88.4 (self, direct).
Compare the FY2027 additions, removals and billable-status changes
What does E88.4 mean in FY2027?
The official ICD-10-CM descriptor is Mitochondrial metabolism disorders. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is E88.4 billable in FY2027?
The FY2027 order file marks E88.4 as a nonbillable heading. Select a complete billable child code.
Does E88.4 map to an HCC?
Risk-model mapping is not applicable to this nonbillable heading. Check a complete billable child code.
Source: CMS FY2027 ICD-10-CM order file. Payment model: CMS CY 2027 Rate Announcement. Read the FY2027 Official Guidelines.
Review the FY2026 April edition