Is ICD-10-CM code M46 billable?

No, M46 (Other inflammatory spondylopathies) 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 M46 belong to?

M46 belongs to Chapter 13 of the ICD-10-CM tabular list: M00–M99 (Diseases of the Musculoskeletal System and Connective Tissue).

M46Not billable, use a more specific code below

Other inflammatory spondylopathies

In Spondylopathies (M45-M49), chapter 13: Diseases of the Musculoskeletal System and Connective Tissue

70 billable codes under M46: 19 are a CC; 19 map to HCC 92 (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis).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.

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 M46

M46 can't be used on a claim. Pick a billable code below; grey headings group them.

M46 MS-DRGs

As the principal diagnosis, the billable codes under M46 group to these 8 MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 551 Medical Back Problems with MCC (51 of 70 codes)
DRG 552 Medical Back Problems without MCC (51 of 70 codes)
DRG 456 Spinal Fusion Except Cervical with Spinal Curvature, Malignancy, or Infection with MCC (29 of 70 codes)
DRG 457 Spinal Fusion Except Cervical with Spinal Curvature, Malignancy, or Infection with CC (29 of 70 codes)
DRG 458 Spinal Fusion Except Cervical with Spinal Curvature, Malignancy, or Infection without CC/MCC (29 of 70 codes)
DRG 539 Osteomyelitis with MCC (19 of 70 codes)
DRG 540 Osteomyelitis with CC (19 of 70 codes)
DRG 541 Osteomyelitis without CC/MCC (19 of 70 codes)

Other codes that refer to M46

Notes on these codes point to M46.

G55 Excludes1: nerve root compression (due to) (in) spondylopathies (M46.-, M48.-)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a type of arthritis of the spine. It causes inflammation (swelling) between your vertebrae (the bones that make up your spine) and the joints between your spine and pelvis. AS inflammation can cause stiffness and make it difficult to move and bend.

Code history

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