Z18.31 — Retained animal quills or spines
Is Z18.31 billable?
Yes — Z18.31 is billable for FY2027. Z18.31 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. Z18.31 may be submitted for encounters from October 1, 2026 through September 30, 2027.
Z18.31 at a glance
| Code | Z18.31 |
|---|---|
| Description | Retained animal quills or spines |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to Z18.31?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name Z18.31 directly.
CMS will reject this code as the principal diagnosis on an inpatient claim. It describes something other than the condition chiefly responsible for the admission.
Which MS-DRGs does Z18.31 group to?
Z18.31 sits in MDC 23 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 951Other Factors Influencing Health Statusmedical
How is Z18.31 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Z18.31. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Retained › foreign body fragments › animal quillor spines
- Retained › foreign body fragments › quill
- Retained › foreign body fragments › spine
- Retained › fragments › animal quillor spines
- Retained › fragments › quill
- Retained › fragments › spine
Excludes1 — never code together — inherited from Z18
The conditions below can never be reported together with Z18.31 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- artificial joint prosthesis status (Z96.6-)
- foreign body accidentally left during a procedure (T81.5-)
- foreign body entering through orifice (T15-T19)
- in situ cardiac device (Z95.-)
- organ or tissue replaced by means other than transplant (Z96.-, Z97.-)
- organ or tissue replaced by transplant (Z94.-)
- personal history of retained foreign body fully removed Z87.821
- superficial foreign body (non-embedded splinter) - code to superficial foreign body, by site
How long has Z18.31 existed?
Z18.31 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.