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FY2027 ICD-10-CM reference

M31.5: Giant cell arteritis with polymyalgia rheumatica

By the HCC Buddy Coding Team

The official ICD-10-CM descriptor is Giant cell arteritis with polymyalgia rheumatica. 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.

Oct to Dec 2026, PY2027

CMS-HCC V28

Mapped
  • HCC 94Systemic Lupus Erythematosus and Other Specif...Coefficient 0.268 (CNA, PY2027)

CMS-HCC V24

Not used by CMS

ESRD

Mapped
  • HCC 40Rheumatoid Arthritis and Inflammatory Connect...Coefficient 0.058 (Dialysis CE, PY2027)

RxHCC

Mapped
  • HCC 84Systemic Lupus Erythematosus and Other System...Coefficient 0.114 (MA-PD CE non-low aged, PY2027)

PACE (CMS-HCC V22 component)

Mapped
  • HCC 40Rheumatoid Arthritis and Inflammatory Connect...

PACE ESRD (ESRD V21 component)

Mapped
  • HCC 40Rheumatoid Arthritis and Inflammatory Connect...

PACE RxHCC (2018/2019 component)

Mapped
  • HCC 84Systemic Lupus Erythematosus and Other System...

Jan to Sep 2027, PY2028

CMS-HCC V28

Not published by CMS

CMS-HCC V24

Not published by CMS

ESRD

Not published by CMS

RxHCC

Not published by CMS

PACE (CMS-HCC V22 component)

Not published by CMS

PACE ESRD (ESRD V21 component)

Not published by CMS

PACE RxHCC component

Not published by CMS

Oct to Dec 2026, BY2026

HHS-HCC

Pending

Jan to Sep 2027, BY2027

HHS-HCC

Not published by CMS

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 an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

Source: M00-M99 (chapter, inherited).

Excludes2

arthropathic psoriasis (L40.5-)

Source: M00-M99 (chapter, inherited).

Excludes2

certain conditions originating in the perinatal period (P04-P96)

Source: M00-M99 (chapter, inherited).

Excludes2

certain infectious and parasitic diseases (A00-B99)

Source: M00-M99 (chapter, inherited).

Excludes2

compartment syndrome (traumatic) (T79.A-)

Source: M00-M99 (chapter, inherited).

Excludes2

complications of pregnancy, childbirth and the puerperium (O00-O9A)

Source: M00-M99 (chapter, inherited).

Excludes2

congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)

Source: M00-M99 (chapter, inherited).

Excludes2

endocrine, nutritional and metabolic diseases (E00-E88)

Source: M00-M99 (chapter, inherited).

Excludes2

injury, poisoning and certain other consequences of external causes (S00-T88)

Source: M00-M99 (chapter, inherited).

Excludes2

neoplasms (C00-D49)

Source: M00-M99 (chapter, inherited).

Excludes2

symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Source: M00-M99 (chapter, inherited).

Includes

autoimmune disease NOS

Source: M30-M36 (section, inherited).

Includes

collagen (vascular) disease NOS

Source: M30-M36 (section, inherited).

Includes

systemic autoimmune disease

Source: M30-M36 (section, inherited).

Includes

systemic collagen (vascular) disease

Source: M30-M36 (section, inherited).

Excludes1

autoimmune disease, single organ or single cell-type -code to relevant condition category

Source: M30-M36 (section, inherited).

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 M31.5 mean in FY2027?

The official ICD-10-CM descriptor is Giant cell arteritis with polymyalgia rheumatica. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.

Is M31.5 billable in FY2027?

The FY2027 order file marks M31.5 as billable. Check the complete Tabular instructions and documentation before assigning it.

Does M31.5 map to an HCC?

Oct to Dec 2026, PY2027: CMS-HCC V28 HCC 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders); CMS-HCC V24: Not used by CMS; ESRD HCC 40 (Rheumatoid Arthritis and Inflammatory Connective Tissue Disease); RxHCC HCC 84 (Systemic Lupus Erythematosus and Other Systemic Connective Tissue Disorders). Jan to Sep 2027, PY2028: CMS-HCC V28: Not published by CMS; CMS-HCC V24: Not published by CMS; ESRD: Not published by CMS; RxHCC: Not published by CMS. Oct to Dec 2026, BY2026: HHS-HCC: Pending. Jan to Sep 2027, BY2027: HHS-HCC: Not published by CMS. Base coefficients are reference values, not a member total.

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