2026 ICD-10-CM Diagnosis Code Z18.33Retained wood fragments

ICD-10-CM Codes›Z00–Z99›Z18›Z18

ICD-10-CM Z18.33
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Z18.33 is a billable ICD-10-CM diagnosis code for retained wood fragments. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified status.

Code Identity

ICD-10-CM Code
Z18.33
Billable Status
Yes — Valid for Submission
Code Describes
Retained wood fragments
Short Description
Retained wood fragments
Same as the full description in the CMS dataset.
Parent Code
Z18.3
Retained organic fragments

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ18Retained foreign body fragments
CategoryZ18Retained foreign body fragments
This CodeZ18.33Retained wood fragments

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z18.33.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Present on Admission (POA)Billing

Z18.33 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Foreign body in heel
  • Foreign body in lip
  • Splinter in ankle
  • Splinter in axilla
  • Splinter in back
  • Splinter in breast
  • Splinter in buttock
  • Splinter in elbow
  • Splinter in face
  • Splinter in foot
  • Splinter in groin
  • Splinter in hip
  • Splinter in knee
  • Splinter in lower leg
  • Splinter in neck
  • Splinter in shoulder
  • Splinter in thigh
  • Splinter in toe
  • Splinter in wrist
  • Wood splinter in abdomen
  • Wood splinter in ankle
  • Wood splinter in anterior region of neck
  • Wood splinter in axilla
  • Wood splinter in back
  • Wood splinter in breast
  • Wood splinter in buttock
  • Wood splinter in calf
  • Wood splinter in cheek
  • Wood splinter in chest
  • Wood splinter in dorsum of foot
  • Wood splinter in ear region
  • Wood splinter in elbow
  • Wood splinter in eye region
  • Wood splinter in face
  • Wood splinter in foot
  • Wood splinter in forehead
  • Wood splinter in genitalia
  • Wood splinter in great toe
  • Wood splinter in groin
  • Wood splinter in head
  • Wood splinter in head and neck
  • Wood splinter in head and/or neck
  • Wood splinter in heel
  • Wood splinter in hip
  • Wood splinter in knee
  • Wood splinter in lip
  • Wood splinter in lower leg
  • Wood splinter in mouth
  • Wood splinter in neck
  • Wood splinter in perineum
  • Wood splinter in pharynx
  • Wood splinter in shin
  • Wood splinter in shoulder
  • Wood splinter in sole of foot
  • Wood splinter in thigh
  • Wood splinter in toe
  • Wood splinter in trunk
  • Wood splinter in wrist

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Retained
      • foreign body fragments (type of)
        • wood
    • Retained
      • fragments (type of )
        • wood

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR FAC025
Other specified status
Default principal diagnosis: inpatient No · outpatient Yes

Patient EducationClinical

Foreign Bodies

If you've ever gotten a splinter or had sand in your eye, you've had experience with a foreign body. A foreign body is something that is stuck inside you but isn't supposed to be there. You may inhale or swallow a foreign body, or you may get one from an injury to almost any part of your body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Z18.33 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
V90.33 Retained wood fragments
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Z18.33Overview

Is Z18.33 (Retained organic fragments) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report retained wood fragments on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can Z18.33 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because retained wood fragments describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z18.33 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for retained wood fragments on inpatient claims.

What is the ICD-9 equivalent of Z18.33?

Under the General Equivalence Mappings, retained wood fragments converts to ICD-9-CM V90.33 (retained wood fragments). The mapping is a direct match.