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FY2027 ICD-10-CM reference

S58.919A: Complete traumatic amputation of unspecified forearm, level unspecified, initial encounter

By the HCC Buddy Coding Team

The official ICD-10-CM descriptor is Complete traumatic amputation of unspecified forearm, level unspecified, initial encounter. 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.

CMS-HCC V28

  • HCC 405: Traumatic Amputations and Complications · RAF 0.598, Community Non-Dual Aged (CNA)

Payment year 2027, 2026 dates of service. HCC from the CMS 2027 Initial ICD-10-CM Mappings; RAF from the CMS-HCC V28 relative factors. For 2027 dates of service, CMS has not yet published the payment year 2028 mappings.

CMS-HCC V24

Not used for payment year 2027 Medicare Advantage payment

ESRD

  • HCC 173: Traumatic Amputations and Complications

Coefficient pending: payment year 2027 coefficients for this model are not yet verified, so no RAF is shown. Mapping: PY2026 CMS mapping; CMS 2027 initial file unchanged.

PACE

Source verification pending

RxHCC

No category in the PY2026 CMS mapping; CMS 2027 initial file unchanged

HHS-HCC

  • HCC 234: Traumatic Amputations and Amputation Complications

RAF not applicable: HHS-HCC weights vary by metal level. Mapping: HHS-HCC 2026 benefit year.

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

Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code

Source: S00-T88 (chapter, inherited).

Instructional note

code to identify any retained foreign body, if applicable (Z18.-)

Source: S00-T88 (chapter, inherited).

Excludes2

birth trauma (P10-P15)

Source: S00-T88 (chapter, inherited).

Excludes2

obstetric trauma (O70-O71)

Source: S00-T88 (chapter, inherited).

Instructional note

The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

Source: S00-T88 (chapter, inherited).

Excludes2

burns and corrosions (T20-T32)

Source: S50-S59 (section, inherited).

Excludes2

frostbite (T33-T34)

Source: S50-S59 (section, inherited).

Excludes2

injuries of wrist and hand (S60-S69)

Source: S50-S59 (section, inherited).

Excludes2

insect bite or sting, venomous (T63.4)

Source: S50-S59 (section, inherited).

Instructional note

An amputation not identified as partial or complete should be coded to complete

Source: S58 (category, inherited).

Excludes1

traumatic amputation of wrist and hand (S68.-)

Source: S58 (category, inherited).

Seventh-character instruction

The appropriate 7th character is to be added to each code from category S58

Source: S58 (category, inherited).

Instructional note

initial encounter

Source: S58 (category, inherited).

Instructional note

subsequent encounter

Source: S58 (category, inherited).

Instructional note

sequela

Source: S58 (category, inherited).

Excludes1

traumatic amputation of wrist (S68.-)

Source: S58.9 (self, inherited).

Seventh-character definitions

  • A: initial encounter
  • D: subsequent encounter
  • S: sequela

Source: CMS FY2027 Tabular List and Alphabetic Index.

Open Tabular instructions and code details

Compare the FY2027 additions, removals and billable-status changes

What does S58.919A mean in FY2027?

The official ICD-10-CM descriptor is Complete traumatic amputation of unspecified forearm, level unspecified, initial encounter. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.

Is S58.919A billable in FY2027?

The FY2027 order file marks S58.919A as billable. Check the complete Tabular instructions and documentation before assigning it.

Does S58.919A map to an HCC?

In the CMS 2027 Initial ICD-10-CM Mappings (payment year 2027, 2026 dates of service), S58.919A maps to CMS-HCC V28 HCC 405 (Traumatic Amputations and Complications). 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 173; no RxHCC category. Coefficients for these models are pending verification for payment year 2027. HHS-HCC: HCC 234 under the HHS-HCC 2026 benefit year mapping (no RAF; HHS-HCC weights vary by metal level). 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