Z05.43 ICD-10-CM Code: Observation and evaluation of newborn for suspected immunologic condition ruled out
HCC Buddy Code Card
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FY 2026 Apr update / Factors influencing health status and contact with health services (Z00-Z99) / Persons encountering health services for examinations (Z00-Z13)
Z05.43
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceObservation and evaluation of newborn for suspected immunologic condition ruled out
A newborn is observed and evaluated for a suspected immune system condition, but testing rules out any immunologic problems.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for Z05.43 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for Z05.43 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for Z05.43 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for Z05.43 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for Z05.43 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for Z05.43 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for Z05.43 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is Z05.43 an HCC code?
No. Z05.43 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- Z05.43
- Description
- Observation and evaluation of newborn for suspected immunologic condition ruled out
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
Z05.43 is the ICD-10-CM diagnosis code for observation and evaluation of newborn for suspected immunologic condition ruled out. A newborn is observed and evaluated for a suspected immune system condition, but testing rules out any immunologic problems. Z05.43 sits in the ICD-10-CM chapter for factors influencing health status and contact with health services (z00-z99), within the section covering persons encountering health services for examinations (z00-z13).
Z05.43 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Apply this code when immune function was evaluated due to maternal factors or clinical concerns but testing was normal.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Z05.43 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Apply this code when immune function was evaluated due to maternal factors or clinical concerns but testing was normal
- •Document the specific immunologic concern that prompted evaluation