S23.421A — Sprain of chondrosternal joint, initial encounter
Is S23.421A billable?
Yes — S23.421A is billable for FY2027. S23.421A is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. S23.421A may be submitted for encounters from October 1, 2026 through September 30, 2027.
S23.421A at a glance
| Code | S23.421A |
|---|---|
| Description | Sprain of chondrosternal joint, 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 S23.421A?
In S23.421A, the 7th character A means initial encounter. The 7th character is required for S23.421A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does S23.421A group to?
S23.421A sits in MDC 04 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.
- 205Other Respiratory System Diagnoses with MCCmedical
- 206Other Respiratory System Diagnoses without MCCmedical
How is S23.421A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S23.421, the nearest indexed parent of S23.421A. Use them to find the family, then select the specific code.
- Sprain › chondrosternal (joint) (ligament)
- Sprain › sternum › chondrosternal joint (joint) (ligament)
Use additional code — inherited from Chapter 19
Report an additional code alongside S23.421A to fully describe the condition. S23.421A 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 S23.421A, but a patient may have both at the same time. When documentation supports it, S23.421A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S20-S29
The conditions below are not part of S23.421A, but a patient may have both at the same time. When documentation supports it, S23.421A and the excluded code may both be reported.
- burns and corrosions (T20-T32)
- effects of foreign body in bronchus (T17.5)
- effects of foreign body in esophagus (T18.1)
- effects of foreign body in lung (T17.8)
- effects of foreign body in trachea (T17.4)
- frostbite (T33-T34)
- injuries of axilla
- injuries of clavicle
- injuries of scapular region
- injuries of shoulder
- insect bite or sting, venomous (T63.4)
Excludes2 — not included here — inherited from S23
The conditions below are not part of S23.421A, but a patient may have both at the same time. When documentation supports it, S23.421A and the excluded code may both be reported.
Code also — inherited from S23
Two codes may be needed to describe the condition fully. Whether S23.421A is sequenced first depends on the reason for the encounter.
- any associated open wound
How long has S23.421A existed?
S23.421A 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.