2027 ICD-10-CM Diagnosis Code Z03.821Encounter for observation for suspected ingested foreign body ruled out

ICD-10-CM Codes›Z00–Z99›Z00-Z13›Z03

ICD-10-CM Z03.821
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z03.821 is a billable ICD-10-CM diagnosis code for encounter for observation for suspected ingested foreign body ruled out. 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 Encounter for observation and examination for conditions ruled out (excludes infectious disease, neoplasm, mental disorders).

Code Identity

ICD-10-CM Code
Z03.821
Billable Status
Yes — Valid for Submission
Code Describes
Encounter for observation for suspected ingested foreign body ruled out
Short Description
Enctr for observation for suspected ingested fb ruled out
Parent Code
Z03.82
Encounter for observation for suspected foreign body ruled out

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ00-Z13Persons encountering health services for examinations
CategoryZ03Encounter for medical observation for suspected diseases and conditions ruled out
This CodeZ03.821Encounter for observation for suspected ingested foreign body ruled out

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z03.821.

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

Z03.821 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Persons encountering health services for examinations (Z00-Z13).

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z03.821: its own notes plus those printed at Z03.82, Z03, block Z00-Z13, and Chapter 21. A note printed at a category, block or chapter applies to every code under it.

Excludes1

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

From Z03.82 Encounter for observation for suspected foreign body ruled out applies to 3 codes
  • retained foreign body (Z18.-)
  • retained foreign body in eyelid (H02.81)
  • residual foreign body in soft tissue (M79.5)
From Z03 Encounter for medical observation for suspected diseases and conditions ruled out applies to 14 codes
  • contact with and (suspected) exposures hazardous to health (Z77.-)
  • encounter for observation and evaluation of newborn for suspected diseases and conditions ruled out (Z05.-)
  • person with feared complaint in whom no diagnosis is made (Z71.1)
  • signs or symptoms under study- code to signs or symptoms

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Z03.82 Encounter for observation for suspected foreign body ruled out applies to 3 codes
  • confirmed foreign body ingestion or aspiration including:
  • foreign body in alimentary tract (T18)
  • foreign body in ear (T16)
  • foreign body on external eye (T15)
  • foreign body in respiratory tract (T17)
From Block Z00-Z13 Persons encountering health services for examinations applies to 156 codes
  • examinations related to pregnancy and reproduction (Z30-Z36, Z39.-)

Notes

General instructions on how these codes are used.

From Block Z00-Z13 Persons encountering health services for examinations applies to 156 codes
  • Nonspecific abnormal findings disclosed at the time of these examinations are classified to categories R70-R94.
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 Z03.821, its category, or a range that includes it.

Excludes1 3

These codes carry an Excludes1 note naming Z03.821: they are not reported together with it, unless the two conditions are unrelated.

  • F63.2 Kleptomania
    shoplifting as the reason for observation for suspected mental disorder (Z03.8) names Z03.8, which includes this code
  • Z01 Encounter for other special examination without complaint, suspected or reported diagnosis
    encounter for examination for suspected conditions, proven not to exist (Z03.-) names Z03.-, which includes this code
  • Z71.1 Person with feared health complaint in whom no diagnosis is made
    medical observation for suspected diseases and conditions proven not to exist (Z03.-) names Z03.-, 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 FAC003
Encounter for observation and examination for conditions ruled out (excludes infectious disease, neoplasm, mental disorders)
Default principal diagnosis: inpatient No · outpatient Yes

Code History & ChangesHistory

Replacement Z03.821 replaces the following previously assigned code(s):

  • Z03.89 - Encntr for obs for oth suspected diseases and cond ruled out
FY 2021AddedAdded to the ICD-10-CM code setEffective October 1, 2020.
FY 2022–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Z03.821Overview

Is Z03.821 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report encounter for observation for suspected ingested foreign body ruled out on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z03.821 group to?

On inpatient claims, encounter for observation for suspected ingested foreign body ruled out 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 Z03.821 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because encounter for observation for suspected ingested foreign body ruled out describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z03.821 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 encounter for observation for suspected ingested foreign body ruled out on inpatient claims. The code appears in the Persons encountering health services for examinations (Z00-Z13) range of the CMS exempt list.

Can Z03.821 be reported with a code from Z18?

Not as a rule. The Excludes1 note at Z03.82, which applies to Z03.821, lists "retained foreign body (Z18.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).