S09.309A — Unspecified injury of unspecified middle and inner ear, initial encounter
Is S09.309A billable?
Yes, but S09.309A will trip a Medicare edit. S09.309A is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists S09.309A 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.
S09.309A at a glance
| Code | S09.309A |
|---|---|
| Description | Unspecified injury of unspecified middle and inner ear, initial encounter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "A" | initial encounter |
What does the 7th character "A" mean in S09.309A?
In S09.309A, the 7th character A means initial encounter. The 7th character is required for S09.309A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
What Medicare edits apply to S09.309A?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name S09.309A 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 S09.309A group to?
S09.309A sits in MDC 03 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.
- 154Other Ear, Nose, Mouth and Throat Diagnoses with MCCmedical
- 155Other Ear, Nose, Mouth and Throat Diagnoses with CCmedical
- 156Other Ear, Nose, Mouth and Throat Diagnoses without CC/MCCmedical
As a secondary diagnosis, S09.309A is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is S09.309A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S09.30, the nearest indexed parent of S09.309A. Use them to find the family, then select the specific code.
- Injury › eustachian tube
- Injury › labyrinth, ear
- Injury › middle ear
- Injury › ear › middle
Excludes1 — never code together — inherited from S09.3
The conditions below can never be reported together with S09.309A on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- injury to ear NOS (S09.91-)
Use additional code — inherited from Chapter 19
Report an additional code alongside S09.309A to fully describe the condition. S09.309A 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 S09.309A, but a patient may have both at the same time. When documentation supports it, S09.309A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S00-S09
The conditions below are not part of S09.309A, but a patient may have both at the same time. When documentation supports it, S09.309A and the excluded code may both be reported.
- burns and corrosions (T20-T32)
- effects of foreign body in ear (T16)
- effects of foreign body in larynx (T17.3)
- effects of foreign body in mouth NOS (T18.0)
- effects of foreign body in nose (T17.0-T17.1)
- effects of foreign body in pharynx (T17.2)
- effects of foreign body on external eye (T15.-)
- frostbite (T33-T34)
- insect bite or sting, venomous (T63.4)
Excludes2 — not included here — inherited from S09.3
The conditions below are not part of S09.309A, but a patient may have both at the same time. When documentation supports it, S09.309A and the excluded code may both be reported.
Code also — inherited from S00-S09
Two codes may be needed to describe the condition fully. Whether S09.309A is sequenced first depends on the reason for the encounter.
- for any associated infection
How long has S09.309A existed?
S09.309A 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.