Is M08 a billable ICD-10-CM code?

No. M08 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does M08 sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Inflammatory polyarthropathies (M05-M14).

What cannot be coded together with M08?

M08 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

M08

M08 — Juvenile arthritis

Non-billable headerICD-10-CM

M08 is a non-billable header ICD-10-CM code for juvenile arthritis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

arthropathy in Whipple's disease (M14.8)
Felty's syndrome (M05.0)
juvenile dermatomyositis (M33.0-)
psoriatic juvenile arthropathy (L40.54)

Code also

Both codes may be needed to describe the encounter fully. Sequencing depends on the reason for the visit.

any associated underlying condition, such as:
regional enteritis [Crohn's disease] (K50.-)
ulcerative colitis (K51.-)

Other codes that can never be billed with M08

These codes carry an Excludes1 note pointing at M08. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading M08 alone.

M05Rheumatoid arthritis with rheumatoid factor
M06.1Adult-onset Still's disease
M08.9Juvenile arthritis, unspecified
M45Ankylosing spondylitis

Risk adjustment

M08 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 to one of these instead M08

7 child codes. Green means billable.

Questions about M08

Is M08 a billable ICD-10-CM code?: No. M08 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does M08 sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Inflammatory polyarthropathies (M05-M14).
What cannot be coded together with M08?: M08 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.