M84.329K — Stress fracture, unspecified humerus, subsequent encounter for fracture with nonunion
Is M84.329K billable?
Yes, but M84.329K will trip a Medicare edit. M84.329K is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists M84.329K under Medicare Code Editor edit 20, “Unspecified code” — meaning a code specifying laterality (right, left or bilateral) exists in the same family. On an inpatient claim this triggers the edit, because CMS holds that there are very limited circumstances in which laterality cannot be documented.
M84.329K at a glance
| Code | M84.329K |
|---|---|
| Description | Stress fracture, unspecified humerus, subsequent encounter for fracture with nonunion |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "K" | subsequent encounter for fracture with nonunion |
What does the 7th character "K" mean in M84.329K?
In M84.329K, the 7th character K means subsequent encounter for fracture with nonunion. The 7th character is required for M84.329K to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
What Medicare edits apply to M84.329K?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name M84.329K directly.
A code specifying laterality (right, left or bilateral) exists in the same family. CMS holds that there are very limited circumstances in which laterality cannot be documented.
Which MS-DRGs does M84.329K group to?
M84.329K sits in MDC 08 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 564Other Musculoskeletal System and Connective Tissue Diagnoses with MCCmedical
- 565Other Musculoskeletal System and Connective Tissue Diagnoses with CCmedical
- 566Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCCmedical
As a secondary diagnosis, M84.329K is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is M84.329K listed in the Alphabetic Index?
The Alphabetic Index lists these routes under M84.32, the nearest indexed parent of M84.329K. Use them to find the family, then select the specific code.
- Fracture, traumatic › stress › humerus (abduction) (adduction) (separation)
Excludes1 — never code together — inherited from M84.3
The conditions below can never be reported together with M84.329K on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from M84.3
Report an additional code alongside M84.329K to fully describe the condition. M84.329K is sequenced first.
- external cause code(s) to identify the cause of the stress fracture
Excludes2 — not included here — inherited from Chapter 13
The conditions below are not part of M84.329K, but a patient may have both at the same time. When documentation supports it, M84.329K and the excluded code may both be reported.
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Excludes2 — not included here — inherited from M84
The conditions below are not part of M84.329K, but a patient may have both at the same time. When documentation supports it, M84.329K and the excluded code may both be reported.
- traumatic fracture of bone-see fracture, by site
Excludes2 — not included here — inherited from M84.3
The conditions below are not part of M84.329K, but a patient may have both at the same time. When documentation supports it, M84.329K and the excluded code may both be reported.
How long has M84.329K existed?
M84.329K has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.