Is ICD-10-CM code M31 billable?

No, M31 (Other necrotizing vasculopathies) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code M31 belong to?

M31 belongs to Chapter 13 of the ICD-10-CM tabular list: M00–M99 (Diseases of the Musculoskeletal System and Connective Tissue).

M31Not billable, use a more specific code below

Other necrotizing vasculopathies

In Systemic connective tissue disorders (M30-M36), chapter 13: Diseases of the Musculoskeletal System and Connective Tissue

13 billable codes under M31: 3 are an MCC, 8 are a CC; all map to HCC 93 (Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders), HCC 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders), HCC 112 (Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions) and 1 more HCCs.A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Also applies, from Systemic connective tissue disorders (M30-M36)

These notes sit on M30-M36 and apply to every code under it, including M31.

Includes: conditions that are coded here

autoimmune disease NOS
collagen (vascular) disease NOS
systemic autoimmune disease
systemic collagen (vascular) disease

Excludes1: not coded here, use a different code

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

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers site and laterality, acute injury versus chronic musculoskeletal conditions, 7th characters for pathologic fractures, osteoporosis with or without current fracture, and multisystem inflammatory syndrome.

Site and laterality (page 60)
Acute traumatic versus chronic or recurrent musculoskeletal conditions (page 61)
Coding of Pathologic Fractures (page 61)
Osteoporosis (page 61)
Multisystem Inflammatory Syndrome (page 62)

Read Section I.C.13 (page 60)

All codes under M31

M31 can't be used on a claim. Pick a billable code below; grey headings group them.

M31 MS-DRGs

As the principal diagnosis, the billable codes under M31 group to these 9 MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 545 Connective Tissue Disorders with MCC (8 of 13 codes)
DRG 546 Connective Tissue Disorders with CC (8 of 13 codes)
DRG 547 Connective Tissue Disorders without CC/MCC (8 of 13 codes)
DRG 542 Pathological Fractures and Musculoskeletal and Connective Tissue Malignancy with MCC (3 of 13 codes)
DRG 543 Pathological Fractures and Musculoskeletal and Connective Tissue Malignancy with CC (3 of 13 codes)
DRG 544 Pathological Fractures and Musculoskeletal and Connective Tissue Malignancy without CC/MCC (3 of 13 codes)
DRG 299 Peripheral Vascular Disorders with MCC (2 of 13 codes)
DRG 300 Peripheral Vascular Disorders with CC (2 of 13 codes)
DRG 301 Peripheral Vascular Disorders without CC/MCC (2 of 13 codes)

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.