S13.120A — Subluxation of C1/C2 cervical vertebrae, initial encounter
Is S13.120A billable?
Yes — S13.120A is billable for FY2027. S13.120A is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. S13.120A may be submitted for encounters from October 1, 2026 through September 30, 2027.
S13.120A at a glance
| Code | S13.120A |
|---|---|
| Description | Subluxation of C1/C2 cervical vertebrae, 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 S13.120A?
In S13.120A, the 7th character A means initial encounter. The 7th character is required for S13.120A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does S13.120A group to?
S13.120A 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.
- 551Medical Back Problems with MCCmedical
- 552Medical Back Problems without MCCmedical
As a secondary diagnosis, S13.120A 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 S13.120A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S13.120, the nearest indexed parent of S13.120A. Use them to find the family, then select the specific code.
- Subluxation › vertebral › traumatic › cervical › atlantoaxial joint
- Subluxation › vertebral › traumatic › cervical › joint between › C1 and C2
Use additional code — inherited from Chapter 19
Report an additional code alongside S13.120A to fully describe the condition. S13.120A 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 S13.120A, but a patient may have both at the same time. When documentation supports it, S13.120A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S10-S19
The conditions below are not part of S13.120A, but a patient may have both at the same time. When documentation supports it, S13.120A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S13
The conditions below are not part of S13.120A, but a patient may have both at the same time. When documentation supports it, S13.120A and the excluded code may both be reported.
- strain of muscle or tendon at neck level (S16.1)
Excludes2 — not included here — inherited from S13.1
The conditions below are not part of S13.120A, but a patient may have both at the same time. When documentation supports it, S13.120A and the excluded code may both be reported.
- fracture of cervical vertebrae (S12.0-S12.3-)
Code also — inherited from S13
Two codes may be needed to describe the condition fully. Whether S13.120A is sequenced first depends on the reason for the encounter.
- any associated open wound
Code also — inherited from S13.1
Two codes may be needed to describe the condition fully. Whether S13.120A is sequenced first depends on the reason for the encounter.
How long has S13.120A existed?
S13.120A 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.