2026 ICD-10-CM Diagnosis Code M84.339AStress fracture, unspecified ulna and radius, initial encounter for fracture
M84.339A is a billable ICD-10-CM diagnosis code for stress fracture, unspecified ulna and radius, initial encounter for fracture. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 542 through 544. Coders also document this condition as stress fracture of radius. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Stress fracture, initial encounter.
Code Identity
Code Classification
Quality Payment Program MeasuresBilling
Medicare quality measures that can apply when M84.339A is part of the patient record.
Communication with the Physician or Other Clinician Managing On-Going Care Post-Fracture for Men and Women Aged 50 Years and Older
High Priority: YES
Measure Type: Process
Submission Methods: Claims, Registry
Description: Percentage of patients aged 50 years and older treated for a fracture with documentation of communication, between the physician treating the fracture and the physician or other clinician managing the patient's on-going care, that a fracture occurred and that the patient was or should be considered for osteoporosis treatment or testing. This measure is submitted by the physician who treats the fracture and who therefore is held accountable for the communication.
Osteoporosis Management in Women Who Had a Fracture
High Priority: NO
Measure Type: Process
Submission Methods: Claims, Registry
Description: The percentage of women 50-85 years of age who suffered a fracture and who had either a bone mineral density (BMD) test or prescription for a drug to treat osteoporosis in the six months after the fracture.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Stress fracture of radius
- Stress fracture of ulna
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Arm Injuries and Disorders
Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.
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Convert M84.339A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M84.339AOverview
Is M84.339A (Stress fracture, unspecified ulna and radius) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report stress fracture, unspecified ulna and radius, initial encounter for fracture on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in M84.339A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for stress fracture, unspecified ulna and radius, such as an emergency visit or first evaluation.
What MS-DRG does M84.339A group to?
When stress fracture, unspecified ulna and radius, initial encounter for fracture is the principal diagnosis on an inpatient stay, it groups to MS-DRG 542, 543, 544, with relative weights from 0.7546 to 1.7665 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M84.339A?
Under the General Equivalence Mappings, stress fracture, unspecified ulna and radius, initial encounter for fracture converts to ICD-9-CM 733.95 (stress fracture bone 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.
