Is M35 a billable ICD-10-CM code?

No. M35 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does M35 sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Systemic connective tissue disorders (M30-M36).

What cannot be coded together with M35?

M35 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

M35

M35 — Other systemic involvement of connective tissue

Non-billable headerICD-10-CM

M35 is a non-billable header ICD-10-CM code for other systemic involvement of connective tissue. 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.

reactive perforating collagenosis (L87.1)

Other codes that can never be billed with M35

These codes carry an Excludes1 note pointing at M35. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading M35 alone.

L95Vasculitis limited to skin, not elsewhere classified
M02Postinfective and reactive arthropathies
M24.2Disorder of ligament
M54.0Panniculitis affecting regions of neck and back
M72.8Other fibroblastic disorders
M79.3Panniculitis, unspecified
N16Renal tubulo-interstitial disorders in diseases classified elsewhere
R68.2Dry mouth, unspecified

Risk adjustment

M35 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 M35

10 child codes. Green means billable.

Questions about M35

Is M35 a billable ICD-10-CM code?: No. M35 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does M35 sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Systemic connective tissue disorders (M30-M36).
What cannot be coded together with M35?: M35 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.