S31.657A — Open bite of abdominal wall, left flank with penetration into peritoneal cavity, initial encounter
S31.657A is a billable, specific ICD-10-CM code for open bite of abdominal wall, left flank with penetration into peritoneal cavity, initial encounter. It is valid for submission on a claim.
7th character "A" — initial encounter
The appropriate 7th character is to be added to each code from category S31
- A
- initial encounter
- D
- subsequent encounter
- S
- sequela
Excludes1 inherited from the categories above S31.657A
These are not written on S31.657A, but they bind it: a note on a category applies to every code beneath it. Billing S31.657A with anything listed here is a denial.
Written on S31.65 — Open bite of abdominal wall with penetration into peritoneal cavity
Excludes2 inherited from the categories above S31.657A
Also inherited, and the opposite of Excludes1: these conditions are not part of S31.657A, but a patient can have both, so you may code both.
Risk adjustment
S31.657A does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
S31.657A is named in 12 Medicare coverage policies — 12 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A53057Billing and Coding: Home Health Occupational Therapy
- A53058Billing and Coding: Home Health Physical Therapy
- A53064Billing and Coding: Outpatient Occupational Therapy
- A53065Billing and Coding: Outpatient Physical Therapy
Code history
What changed, and when. Derived by diffing consecutive CMS release files — which matters when you are defending a code assigned under an earlier edition.
- addedFY2024-FY2026
Open bite of abdominal wall, left flank with penetration into peritoneal cavity, initial encounter
Related codes at this level
Codes that share S31.657. If S31.657A is not quite right, the correct code is usually one of these.
Questions about S31.657A
- Is S31.657A a billable ICD-10-CM code?
- Yes. S31.657A is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does S31.657A sit in the tabular list?
- Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Injuries to the abdomen, lower back, lumbar spine, pelvis and external genitals (S30-S39).
- What cannot be coded together with S31.657A?
- S31.657A carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above S31.657A (S31.65, S31) and apply to it just the same.