S42.309A — Unspecified fracture of shaft of humerus, unspecified arm, initial encounter for closed fracture
Is S42.309A billable?
Yes, but S42.309A will trip a Medicare edit. S42.309A is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists S42.309A 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.
More specific alternatives
- S42.311AGreenstick fracture of shaft of humerus, right arm, initial encounter for closed fracture
- S42.321ADisplaced transverse fracture of shaft of humerus, right arm, initial encounter for closed fracture
- S42.331ADisplaced oblique fracture of shaft of humerus, right arm, initial encounter for closed fracture
- S42.341ADisplaced spiral fracture of shaft of humerus, right arm, initial encounter for closed fracture
- S42.351ADisplaced comminuted fracture of shaft of humerus, right arm, initial encounter for closed fracture
- S42.361ADisplaced segmental fracture of shaft of humerus, right arm, initial encounter for closed fracture
- S42.391AOther fracture of shaft of right humerus, initial encounter for closed fracture
S42.309A at a glance
| Code | S42.309A |
|---|---|
| Description | Unspecified fracture of shaft of humerus, unspecified arm, initial encounter for closed fracture |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "A" | initial encounter for closed fracture |
What does the 7th character "A" mean in S42.309A?
In S42.309A, the 7th character A means initial encounter for closed fracture. The 7th character is required for S42.309A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
- Ainitial encounter for closed fractureS42.309A
- Binitial encounter for open fractureS42.309B
- Dsubsequent encounter for fracture with routine healingS42.309D
- Gsubsequent encounter for fracture with delayed healingS42.309G
- Ksubsequent encounter for fracture with nonunionS42.309K
- Psubsequent encounter for fracture with malunionS42.309P
- SsequelaS42.309S
What Medicare edits apply to S42.309A?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name S42.309A 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 S42.309A group to?
S42.309A sits in MDC 08 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 562Fracture, Sprain, Strain and Dislocation Except Femur, Hip, Pelvis and Thigh with MCCmedical
- 563Fracture, Sprain, Strain and Dislocation Except Femur, Hip, Pelvis and Thigh without MCCmedical
As a secondary diagnosis, S42.309A is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG. It also carries Hospital-Acquired Condition category 05.
How is S42.309A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S42.30, the nearest indexed parent of S42.309A. Use them to find the family, then select the specific code.
- Fracture, traumatic › humerus (abduction) (adduction) (separation)
- Fracture, traumatic › humerus › shaft (abduction) (adduction) (separation)
Excludes1 — never code together — inherited from S42
The conditions below can never be reported together with S42.309A on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- traumatic amputation of shoulder and upper arm (S48.-)
Use additional code — inherited from Chapter 19
Report an additional code alongside S42.309A to fully describe the condition. S42.309A is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of S42.309A, but a patient may have both at the same time. When documentation supports it, S42.309A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S40-S49
The conditions below are not part of S42.309A, but a patient may have both at the same time. When documentation supports it, S42.309A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S42
The conditions below are not part of S42.309A, but a patient may have both at the same time. When documentation supports it, S42.309A and the excluded code may both be reported.
- periprosthetic fracture around internal prosthetic shoulder joint (M97.3)
Excludes2 — not included here — inherited from S42.3
The conditions below are not part of S42.309A, but a patient may have both at the same time. When documentation supports it, S42.309A and the excluded code may both be reported.
How long has S42.309A existed?
S42.309A 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.