FY2027 ICD-10-CM reference
E66.2: Morbid (severe) obesity with alveolar hypoventilation
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Morbid (severe) obesity with alveolar hypoventilation. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Billable code. Verified against the official FY2027 order file.
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).
Code first
obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-)
Source: E66 (category, inherited).
Instructional note
code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-)
Source: E66 (category, inherited).
Excludes2
adiposogenital dystrophy (E23.6)
Source: E66 (category, inherited).
Excludes2
lipomatosis dolorosa [Dercum] (E88.2)
Source: E66 (category, inherited).
Excludes2
lipomatosis NOS (E88.2)
Source: E66 (category, inherited).
Excludes2
Prader-Willi syndrome (Q87.11)
Source: E66 (category, inherited).
Instructional note
Obesity hypoventilation syndrome (OHS)
Source: E66.2 (self, direct).
Instructional note
Pickwickian syndrome
Source: E66.2 (self, direct).
Compare the FY2027 additions, removals and billable-status changes
What does E66.2 mean in FY2027?
The official ICD-10-CM descriptor is Morbid (severe) obesity with alveolar hypoventilation. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is E66.2 billable in FY2027?
The FY2027 order file marks E66.2 as billable. Check the complete Tabular instructions and documentation before assigning it.
Does E66.2 map to an HCC?
In the CMS 2027 Initial ICD-10-CM Mappings (payment year 2027, 2026 dates of service), E66.2 maps to CMS-HCC V28 HCC 48 (Morbid Obesity). For 2027 dates of service, CMS has not yet published the payment year 2028 mappings. Under the PY2026 CMS mapping; CMS 2027 initial file unchanged: ESRD HCC 22; no RxHCC category. Coefficients for these models are pending verification for payment year 2027. HHS-HCC: no category in the HHS-HCC 2026 benefit year mapping. CMS-HCC V24: not used for payment year 2027 Medicare Advantage payment (CMS CY 2027 Rate Announcement). The PACE mapping is still pending verification for FY2027.
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