2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z18.33 is a billable ICD-10-CM diagnosis code for retained wood fragments. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 951. 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 the other POA exempt codes in Retained foreign body fragments (Z18).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Foreign body in heel
  • Foreign body in lip
  • Foreign body of cheek
  • Foreign body of dorsum of foot
  • Foreign body of forehead
  • 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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z18.33: its own notes plus those printed at Z18 and Chapter 21. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Z18 Retained foreign body fragments applies to 14 codes
  • embedded fragment (status)
  • embedded splinter (status)
  • retained foreign body status

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Z18 Retained foreign body fragments applies to 14 codes
  • 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

Notes

General instructions on how these codes are used.

From Chapter 21 (Z00-Z99) Factors influencing health status and contact with health services applies to 1,425 codes
  • Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
  • (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
  • (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Z18.33, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming Z18.33: they are not reported together with it, unless the two conditions are unrelated.

  • Z03.82 Encounter for observation for suspected foreign body ruled out
    retained foreign body (Z18.-) names Z18.-, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming Z18.33: its condition is not part of those codes, and both may be reported when the patient has both.

  • Z77 Other contact with and (suspected) exposures hazardous to health
    retained foreign body (Z18.-) names Z18.-, which includes this code

Use Additional Code 10

These codes say to use an additional code from the note, and Z18.33 is one of the codes named.

  • H02.81 Retained foreign body in eyelid
    code to identify the type of retained foreign body (Z18.-) names Z18.-, which includes this code
  • H05.5 Retained (old) foreign body following penetrating wound of orbit
    code to identify the type of retained foreign body (Z18.-) names Z18.-, which includes this code
  • L92.3 Foreign body granuloma of the skin and subcutaneous tissue
    code to identify the type of retained foreign body (Z18.-) names Z18.-, which includes this code
  • M60.2 Foreign body granuloma of soft tissue, not elsewhere classified
    code to identify the type of retained foreign body (Z18.-) names Z18.-, which includes this code
  • R78 Findings of drugs and other substances, not normally found in blood
    code to identify any retained foreign body, if applicable (Z18.-) names Z18.-, which includes this code
  • R79 Other abnormal findings of blood chemistry
    code to identify any retained foreign body, if applicable (Z18.-) names Z18.-, which includes this code
  • R82 Other and unspecified abnormal findings in urine
    code to identify any retained foreign body, if applicable (Z18.-) names Z18.-, which includes this code
  • Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes
    code to identify any retained foreign body, if applicable (Z18.-) names Z18.-, which includes this code
  • Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source
    to identify any retained foreign body, if applicable (Z18.-) names Z18.-, which includes this code
  • H44.7 Retained (old) intraocular foreign body, nonmagnetic
    code to identify nonmagnetic foreign body (Z18.01-Z18.10, Z18.12, Z18.2-Z18.9) names Z18.2-Z18.9, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Z18.33Overview

What is the ICD-10 code for retained wood fragments?

The ICD-10-CM code for retained wood fragments is Z18.33 (sometimes written as Z1833). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

What MS-DRG does Z18.33 group to?

On inpatient claims, retained wood fragments maps to MS-DRG 951 (other Factors Influencing Health Status), which carries a relative weight of 0.5574. Higher weights mean higher Medicare reimbursement.

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. The code appears in the Retained foreign body fragments (Z18) range of the CMS exempt list.