Is M85.821 a billable ICD-10-CM code?

Yes. M85.821 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does M85.821 sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Disorders of bone density and structure (M80-M85).

What cannot be coded together with M85.821?

M85.821 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 M85.821 (M85.8, M85) and apply to it just the same.

M85.821

M85.821 — Other specified disorders of bone density and structure, right upper arm

Billable / specific codeICD-10-CMright

M85.821 is a billable, specific ICD-10-CM code for other specified disorders of bone density and structure, right upper arm. It is valid for submission on a claim.

Excludes1 inherited from the categories above M85.821

These are not written on M85.821, but they bind it: a note on a category applies to every code beneath it. Billing M85.821 with anything listed here is a denial.

Written on M85.8 — Other specified disorders of bone density and structure

diffuse idiopathic skeletal hyperostosis [DISH] (M48.1)
osteosclerosis congenita (Q77.4)
osteosclerosis fragilitas (generalista) (Q78.2)
osteosclerosis myelofibrosis (D75.81)

Written on M85 — Other disorders of bone density and structure

osteogenesis imperfecta (Q78.0)
osteopetrosis (Q78.2)
osteopoikilosis (Q78.8)
polyostotic fibrous dysplasia (Q78.1)

Risk adjustment

M85.821 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.

Medicare coverage

M85.821 is named in 24 Medicare coverage policies — 17 listing it as supporting medical necessity, and 7 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A58865Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
A58883Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
A58893Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
A59374Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered

Code history

M85.821 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share M85.82. If M85.821 is not quite right, the correct code is usually one of these.

Questions about M85.821

Is M85.821 a billable ICD-10-CM code?: Yes. M85.821 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does M85.821 sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Disorders of bone density and structure (M80-M85).
What cannot be coded together with M85.821?: M85.821 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 M85.821 (M85.8, M85) and apply to it just the same.