Is M45.A a billable ICD-10-CM code?

No. M45.A is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does M45.A sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Spondylopathies (M45-M49).

What cannot be coded together with M45.A?

M45.A carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above M45.A (M45) and apply to it just the same.

M45.A

M45.A — Non-radiographic axial spondyloarthritis

Non-billable headerICD-10-CM

M45.A is a non-billable header ICD-10-CM code for non-radiographic axial spondyloarthritis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 inherited from the categories above M45.A

These are not written on M45.A, but they bind it: a note on a category applies to every code beneath it. Billing M45.A with anything listed here is a denial.

Written on M45 — Ankylosing spondylitis

arthropathy in Reiter's disease (M02.3-)
juvenile (ankylosing) spondylitis (M08.1)

Excludes2 inherited from the categories above M45.A

Also inherited, and the opposite of Excludes1: these conditions are not part of M45.A, but a patient can have both, so you may code both.

Written on M45 — Ankylosing spondylitis

Behçet's disease (M35.2)

Other codes that can never be billed with M45.A

These codes carry an Excludes1 note pointing at M45.A. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading M45.A alone.

G55Nerve root and plexus compressions in diseases classified elsewhere
M05Rheumatoid arthritis with rheumatoid factor

Risk adjustment

M45.A does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code history

M45.A has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Code to one of these instead M45.A

10 child codes. Green means billable.

Related codes at this level

Codes that share M45. If M45.A is not quite right, the correct code is usually one of these.

Questions about M45.A

Is M45.A a billable ICD-10-CM code?: No. M45.A is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does M45.A sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Spondylopathies (M45-M49).
What cannot be coded together with M45.A?: M45.A carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above M45.A (M45) and apply to it just the same.