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Z28.39 ICD-10-CM Code: Other underimmunization status

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 951 — OTHER FACTORS INFLUENCING HEALTH STATUS (MDC 23)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Official Registry Overview & Definition

Other underimmunization status is a billable ICD-10-CM diagnosis code (Z28.39).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for Z28.39 in the official ICD-10-CM tabular list.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • vaccination not carried out

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Delinquent immunization status
  • Lapsed immunization schedule status

Code Also

Additional codes that may be required to fully describe the encounter.

  • Code also, if applicable, encounter for immunization safety counseling (Z71.85)

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code, if applicable, to identify:
  • immunization not carried out because of contraindication (Z28.0-)
  • immunization not carried out because of patient decision for other and unspecified reason (Z28.2-)
  • immunization not carried out because of patient decision for reasons of belief or group pressure (Z28.1)
  • immunization not carried out for other reason (Z28.8-)

Change history

  • FY2022 — 2021-10-01
    Added to the code set
    Other underimmunization status
    FY2022 changes

Verify Before Coding

  • Principal-diagnosis restriction. The Medicare Code Editor lists this code as unacceptable as a principal diagnosis: it describes a circumstance influencing health status rather than a current illness or injury being treated. It is valid as a secondary diagnosis.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Contextual Map

Every relationship of Z28.39 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • Z00-Z99 — Chapter 21: Factors Influencing Health Status and Contact with Health Services (Z00-Z99) (Z00-Z99) [Hierarchy]
  • Z20-Z29 — Persons with potential health hazards related to communicable diseases [Hierarchy]

Referenced by Code Also instructions

  • Z71.85 — Encounter for immunization safety counseling [Code Also](via Z28.-): “, if applicable, immunization not carried out (Z28.-)” · check together

Clinical classification (CCSR)

  • FAC017 — No immunization or underimmunization [CCSR]

Potential MS-DRG

  • DRG 951 — OTHER FACTORS INFLUENCING HEALTH STATUS [MS-DRG]: “OTHER FACTORS INFLUENCING HEALTH STATUS (MDC 23)”

MDC crossing · procedures (1235)

  • MDC 23 — Factors Influencing Health Status and Other Contacts with Health Services [MDC crossing]: “Factors Influencing Health Status and Other Contacts with Health Services — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”
  • F003GKZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Audiovisual Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Audiovisual Equipment — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GMZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Augmentative / Alternative Communication Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Augmentative / Alternative Communication Equipment — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GPZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Computer [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Computer — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GYZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Other Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Other Equipment — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GZZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • and 1230 more

Index entries

  • Delinquent immunization status[Index term]
  • Lapsed immunization schedule status[Index term]
  • Status (post), delinquent immunization[Index term]
  • Status (post), lapsed immunization schedule[Index term]
  • Status (post), underimmunization[Index term]
  • Underimmunization status[Index term]

Nearest codes (22)

  • Z28 — Immunization not carried out and underimmunization status [Sibling]
  • Z28.0 — Immunization not carried out because of contraindication [Sibling]
  • Z28.01 — Immunization not carried out because of acute illness of patient [Sibling]
  • Z28.02 — Immunization not carried out because of chronic illness or condition of patient [Sibling]
  • Z28.03 — Immunization not carried out because of immune compromised state of patient [Sibling]
  • Z28.04 — Immunization not carried out because of patient allergy to vaccine or component [Sibling]
  • Z28.09 — Immunization not carried out because of other contraindication [Sibling]
  • Z28.1 — Immunization not carried out because of patient decision for reasons of belief or group pressure [Sibling]
  • and 14 more

Change history

  • FY2022 — Added to the code set [Change history]

Referenced by Other Codes

Clinical classification (AHRQ CCSR):FAC017 — No immunization or underimmunization.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Potential MS-DRG Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 1 MS-DRG: DRG 951 (MDC 23).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Official ICD-10-CM tabular notes on other codes that name Z28.39 or its code family.

1 Code Also instructions: Z71.85 (via Z28.-).

Nearest Codes in This Family

Official ICD-10-CM classifications closest to Z28.39 in its code family, with their registry titles.

  • Z28.29 — Immunization not carried out because of patient decision for other reason
  • Z28.3 — Underimmunization status
  • Z28.31 — Underimmunization for COVID-19 status
  • Z28.310 — Unvaccinated for COVID-19
  • Z28.311 — Partially vaccinated for COVID-19
  • Z28.8 — Immunization not carried out for other reason
  • Z28.81 — Immunization not carried out due to patient having had the disease
  • Z28.82 — Immunization not carried out because of caregiver refusal
  • Z28.83 — Immunization not carried out due to unavailability of vaccine
  • Z28.89 — Immunization not carried out for other reason

View all codes in the Z28 family

Indexed Clinical Terms (6)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Delinquent immunization status
  • Lapsed immunization schedule status
  • Status (post), delinquent immunization
  • Status (post), lapsed immunization schedule
  • Status (post), underimmunization
  • Underimmunization status