2027 ICD-10-CM Diagnosis Code Z00.121Encounter for routine child health examination with abnormal findings

ICD-10-CM Codes›Z00–Z99›Z00-Z13›Z00

ICD-10-CM Z00.121
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z00.121 is a billable ICD-10-CM diagnosis code for encounter for routine child health examination with abnormal findings. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 795, 951. The code is restricted by the Medicare Code Editor to pediatric patients (age 0 through 17), not accepted as a principal diagnosis, and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Medical examination/evaluation.

This medical diagnosis code is frequently used in Pediatrics medical specialties to designate conditions such routine child health examination.

Code Identity

ICD-10-CM Code
Z00.121
Billable Status
Yes — Valid for Submission
Code Describes
Encounter for routine child health examination with abnormal findings
Short Description
Encounter for routine child health exam w abnormal findings
Parent Code
Z00.12
Encounter for routine child health examination

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ00-Z13Persons encountering health services for examinations
CategoryZ00Encounter for general examination without complaint, suspected or reported diagnosis
This CodeZ00.121Encounter for routine child health examination with abnormal findings

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z00.121.

Pediatric diagnoses
The Medicare Code Editor detects inconsistencies in pediatric cases by checking a patient's age and any diagnosis on the patient's record. The pediatric code edits apply to patients age range is 0–17 years inclusive (e.g., Reye's syndrome, routine child health exam).
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

Z00.121 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).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • 1 year examination abnormal - for observation
  • 1 year examination abnormal - on treatment
  • 1 year examination abnormal - referred
  • 10 day examination abnormal - for observation
  • 10 day examination abnormal - on treatment
  • 10 year examination abnormal - for observation
  • 10 year examination abnormal - on treatment
  • 10 year examination abnormal - referred
  • 15 year examination abnormal - for observation
  • 15 year examination abnormal - on treatment
  • 15 year examination abnormal - referred
  • 18 month examination abnormal - for observation
  • 18 month examination abnormal - on treatment
  • 18 month examination abnormal - referred
  • 2.5 year examination abnormal - for observation
  • 2.5 year examination abnormal - on treatment
  • 2.5 year examination abnormal - referred
  • 3.5 year examination abnormal - for observation
  • 3.5 year examination abnormal - on treatment
  • 3.5 year examination abnormal - referred
  • 4.5 year examination abnormal - for observation
  • 4.5 year examination abnormal - on treatment
  • 4.5 year examination abnormal - referred
  • 6 week examination abnormal - for observation
  • 6 week examination abnormal - on treatment
  • 6 week examination abnormal - referred
  • 8 month examination abnormal - for observation
  • 8 month examination abnormal - on treatment
  • 8 month examination abnormal - referred
  • 8 week examination abnormal - for observation
  • 8 week examination abnormal - on treatment
  • 8 week examination abnormal - referred
  • 8-9 month examination abnormal - for observation
  • 8-9 month examination abnormal - on treatment
  • 8-9 month examination abnormal - referred
  • Abnormal wellness exam
  • Child 21 month examination abnormal - for observation
  • Child 21 month examination abnormal - on treatment
  • Child 21 month examination abnormal: refer
  • Child 3 year exam abnormal - for observation
  • Child 3 year exam abnormal - on treatment
  • Child 3 year exam abnormal - referred
  • Child 39 month examination abnormal - for observation
  • Child 39 month examination abnormal - on treatment
  • Child 39 month examination abnormal - referred
  • Child 6 month examination abnormal - for observation
  • Child 6 month examination abnormal - on treatment
  • Child 6 month examination abnormal - referred
  • Child 7 month examination abnormal - on treatment
  • Child 7 month examination abnormal - referred
  • Seen by pediatric neurologist
  • Seen by pediatric oncologist
  • Seen by pediatrician

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z00.121: its own notes plus those printed at Z00.12, Z00, 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 Z00.12 Encounter for routine child health examination applies to 2 codes
  • health check for child under 29 days old (Z00.11-)
  • health supervision of foundling or other healthy infant or child (Z76.1-Z76.2)
  • newborn health examination (Z00.11-)
From Z00 Encounter for general examination without complaint, suspected or reported diagnosis applies to 13 codes
  • encounter for examination for administrative purposes (Z02.-)

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 Z00 Encounter for general examination without complaint, suspected or reported diagnosis applies to 13 codes
  • encounter for pre-procedural examinations (Z01.81-)
  • special screening examinations (Z11-Z13)
From Block Z00-Z13 Persons encountering health services for examinations applies to 156 codes
  • examinations related to pregnancy and reproduction (Z30-Z36, Z39.-)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

  • code to identify abnormal findings

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 Z00.121, its category, or a range that includes it.

Excludes1 3

These codes carry an Excludes1 note naming Z00.121: they are not reported together with it, unless the two conditions are unrelated.

  • Z00.0 Encounter for general adult medical examination
    general health check-up of infant or child (Z00.12.-) names Z00.12.-, which includes this code
  • Z00.11 Newborn health examination
    health check for child over 28 days old (Z00.12-) names Z00.12-, which includes this code
  • Z02.7 Encounter for issue of medical certificate
    encounter for general medical examination (Z00-Z01, Z02.0-Z02.6, Z02.8-Z02.9) names Z00-Z01, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming Z00.121: its condition is not part of those codes, and both may be reported when the patient has both.

  • Z13.4 Encounter for screening for certain developmental disorders in childhood
    encounter for routine child health examination (Z00.12-) names Z00.12-, 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 FAC014
Medical examination/evaluation
Default principal diagnosis: inpatient No · outpatient Yes

Patient EducationClinical

Health Checkup

Regular checkups with your health care provider are different from appointments for sickness or injury. These checkups include physical exams as well as preventive care. Preventative care may include:

Read the full article at MedlinePlus

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

Convert Z00.121 to ICD-9-CMHistory

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

ICD-9-CM
V20.2 Routin child health exam
Approximate The match is approximate rather than exact.

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 Z00.121Overview

What is the ICD-10 code for encounter for routine child health examination with abnormal findings?

The ICD-10-CM code for encounter for routine child health examination with abnormal findings is Z00.121 (sometimes written as Z00121). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Z00.121 (Encounter for routine child health examination) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report encounter for routine child health examination with abnormal findings on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z00.121 group to?

On inpatient claims, encounter for routine child health examination with abnormal findings maps to MS-DRG 951, 795, with relative weights from 0.2022 to 0.5574 depending on complications. Higher weights mean higher Medicare reimbursement.

Can Z00.121 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because encounter for routine child health examination with abnormal findings describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Who can Z00.121 be reported for?

The Medicare Code Editor checks encounter for routine child health examination with abnormal findings against patient demographics: this code is intended for pediatric patients (age 0 through 17). Claims outside these limits are flagged as inconsistent.