2026 ICD-10-CM Diagnosis Code M85.821Other specified disorders of bone density and structure, right upper arm
ICD-10-CM Codes›M00–M99›M80-M85›M85
- Billable — Valid for Submission
- Not Chronic
M85.821 is a billable ICD-10-CM diagnosis code for other specified disorders of bone density and structure, right upper arm. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 564 through 566. Coders also document this condition as congenital dysplasia of right upper limb. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified bone disease and musculoskeletal deformities.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Congenital dysplasia of right upper limb
- Melorheostosis of humerus
- Melorheostosis of right humerus
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Bone Density
Your bones are made of living tissue. To keep them strong, your body breaks down old bone and replaces it with new bone. But when more bone is broken down than replaced, you lose bone density, also called bone mass. Bone density is a measure of the amount of calcium and other minerals in bone. Bones containing more minerals are denser.
The full article covers:
- What is bone density?
- What can make you lose bone density?
- Is there a test to measure your bone health?
- How can I keep my bones strong?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M85.821 to ICD-9-CMHistory
Code HistoryHistory
Questions About M85.821Overview
Is M85.821 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other specified disorders of bone density and structure, right upper arm on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M85.821 group to?
When other specified disorders of bone density and structure, right upper arm is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 565, 566, with relative weights from 0.7493 to 1.5436 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M85.821?
Under the General Equivalence Mappings, other specified disorders of bone density and structure, right upper arm converts to ICD-9-CM 733.90 (bone & cartilage dis NOS) and 733.99 (bone & cartilage dis NEC). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
