2027 ICD-10-CM Diagnosis Code Z05.43Observation and evaluation of newborn for suspected immunologic condition ruled out

ICD-10-CM Codes›Z00–Z99›Z00-Z13›Z05

ICD-10-CM Z05.43
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z05.43 is a billable ICD-10-CM diagnosis code for observation and evaluation of newborn for suspected immunologic condition ruled out. 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 newborn patients (age 0) 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
Z05.43
Billable Status
Yes — Valid for Submission
Code Describes
Observation and evaluation of newborn for suspected immunologic condition ruled out
Short Description
Obs & eval of NB for suspected immunologic cond ruled out
Parent Code
Z05.4
Observation and evaluation of newborn for suspected genetic, metabolic or immunologic condition ruled out

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ00-Z13Persons encountering health services for examinations
CategoryZ05Encounter for observation and evaluation of newborn for suspected diseases and conditions ruled out
This CodeZ05.43Observation and evaluation of newborn for suspected immunologic condition ruled out

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z05.43.

Perinatal / Newborn diagnoses
The Medicare Code Editor detects inconsistencies in perinatal / newborn cases by checking a patient's age and any diagnosis on the patient's record. The newborn code edits apply to patients age 0 years only; a subset of diagnoses which will only occur during the perinatal or newborn period of age 0 (e.g., tetanus neonatorum, health examination for newborn under 8 days old).

Present on Admission (POA)Billing

Z05.43 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 Z05.43: its own notes plus those printed at block Z00-Z13 and Chapter 21. A note printed at a category, block or chapter applies to every code under it.

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 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 Z05.43, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming Z05.43: they are not reported together with it, unless the two conditions are unrelated.

  • Z03 Encounter for medical observation for suspected diseases and conditions ruled out
    encounter for observation and evaluation of newborn for suspected diseases and conditions ruled out (Z05.-) names Z05.-, which includes this code

Excludes2 5

These codes carry an Excludes2 note naming Z05.43: its condition is not part of those codes, and both may be reported when the patient has both.

  • P00 Newborn affected by maternal conditions that may be unrelated to present pregnancy
    encounter for observation of newborn for suspected diseases and conditions ruled out (Z05.-) names Z05.-, which includes this code
  • P01 Newborn affected by maternal complications of pregnancy
    encounter for observation of newborn for suspected diseases and conditions ruled out (Z05.-) names Z05.-, which includes this code
  • P02 Newborn affected by complications of placenta, cord and membranes
    encounter for observation of newborn for suspected diseases and conditions ruled out (Z05.-) names Z05.-, which includes this code
  • P03 Newborn affected by other complications of labor and delivery
    encounter for observation of newborn for suspected diseases and conditions ruled out (Z05.-) names Z05.-, which includes this code
  • P04 Newborn affected by noxious substances transmitted via placenta or breast milk
    encounter for observation of newborn for suspected diseases and conditions ruled out (Z05.-) names Z05.-, 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 Yes · outpatient Yes

Convert Z05.43 to ICD-9-CMHistory

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

ICD-9-CM
V29.8 NB obsrv oth suspct cond
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement Z05.43 replaces the following previously assigned code(s):

  • P00.89 - Newborn affected by oth maternal conditions
  • P00.89 - Newborn affected by other maternal conditions
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Z05.43Overview

Is Z05.43 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report observation and evaluation of newborn for suspected immunologic condition ruled out on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z05.43 group to?

When observation and evaluation of newborn for suspected immunologic condition ruled out is the principal diagnosis on an inpatient stay, it groups to MS-DRG 951, 795, with relative weights from 0.2022 to 0.5574 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can Z05.43 be reported for?

The Medicare Code Editor checks observation and evaluation of newborn for suspected immunologic condition ruled out against patient demographics: this code is intended for newborn patients (age 0). Claims outside these limits are flagged as inconsistent.

Is Z05.43 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 observation and evaluation of newborn for suspected immunologic condition ruled out on inpatient claims. The code appears in the Persons encountering health services for examinations (Z00-Z13) range of the CMS exempt list.

What is the ICD-9 equivalent of Z05.43?

Under the General Equivalence Mappings, observation and evaluation of newborn for suspected immunologic condition ruled out converts to ICD-9-CM V29.8 (NB obsrv oth suspct cond). The mapping is approximate, so confirm the match fits the documentation.