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  6. 2026 ICD-10-CM Code Z91.0110

2026 ICD-10-CM Diagnosis Code Z91.0110

Allergy to milk products, unspecified

ICD-10-CM Code:
Z91.0110
ICD-10 Code for:
Allergy to milk products, unspecified
Is Billable?
Yes - Valid for Submission
Code Navigator:

Z91.0110 is a billable diagnosis code used to specify a medical diagnosis of allergy to milk products, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2025 through September 30, 2026. The code is exempt from present on admission (POA) reporting for inpatient admissions to general acute care hospitals.

This code describes a circumstance which influences the patient's health status but not a current illness or injury. The code is unacceptable as a principal diagnosis.

Unspecified diagnosis codes like Z91.0110 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Code Classification

  • Factors influencing health status and contact with health services
    Z00–Z99
    • Persons with potential health hazards related to family and personal history and certain conditions influencing health status
      Z77-Z99
      • Personal risk factors, not elsewhere classified
        Z91

Approximate Synonyms

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

  • Allergy to casein
  • Allergy to cattle protein
  • Allergy to cheese
  • Allergy to cow's milk protein
  • Hemosiderosis
  • Milk-induced pulmonary disease in infant
  • Secondary hemosiderosis
  • Secondary pulmonary hemosiderosis

Clinical Information

  • Hemosiderosis

    conditions in which there is a generalized increase in the iron stores of body tissues, particularly of liver and the mononuclear phagocyte system, without demonstrable tissue damage. the name refers to the presence of stainable iron in the tissue in the form of hemosiderin.

  • Hemosiderosis, Pulmonary

    iron deposition within the lung. primary pulmonary hemosiderosis is characterized by hemoptysis; iron-deficiency anemia, and diffuse pulmonary hemorrhage as seen as transient pulmonary infiltrates on radiography. even though large amounts of iron are laid down in the lung, with normal or increased total body iron, anemia occurs because of inability of the erythron to use iron sequestered in pulmonary macrophages.

  • Mononuclear Phagocyte System

    mononuclear cells with pronounced phagocytic ability that are distributed extensively in lymphoid and other organs. it includes macrophages and their precursors; phagocytes; kupffer cells; histiocytes; dendritic cells; langerhans cells; and microglia. the term mononuclear phagocyte system has replaced the former reticuloendothelial system, which also included less active phagocytic cells such as fibroblasts and endothelial cells. (from illustrated dictionary of immunology, 2d ed.)

New 2026 ICD-10-CM Code

Z91.0110 is new to ICD-10-CM code set for the FY 2026, effective October 1, 2025. The National Center for Health Statistics (NCHS) has published an update to the ICD-10-CM diagnosis codes which became effective October 1, 2025. This is a new and revised code for the FY 2026 (October 1, 2025 - September 30, 2026).

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Index of External Cause of Injuries

References found for this diagnosis code in the External Cause of Injuries Index:

    • Allergy, allergic(reaction) (to)
      • food (any) (ingested) NEC
        • status (without reaction)
          • milk products
    • Allergy, allergic(reaction) (to)
      • milk protein
    • History
      • personal (of)
        • allergy (to)
          • food
            • milk products

Code Edits

The Medicare Code Editor (MCE) detects errors and inconsistencies in ICD-10-CM diagnosis coding that can affect Medicare claim validity. These Medicare code edits help medical coders and billing professionals determine when a diagnosis code is not appropriate as a principal diagnosis, does not meet coverage criteria. Use this list to verify whether a code is valid for Medicare billing and to avoid claim rejections or denials due to diagnosis coding issues.

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.

View Edit

Present on Admission (POA)

Z91.0110 is exempt from POA reporting - The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement. Review other POA exempt codes here.

CMS POA Indicator Options and Definitions

POA Indicator: Y

Reason: Diagnosis was present at time of inpatient admission.

CMS Pays CC/MCC DRG? YES

POA Indicator: N

Reason: Diagnosis was not present at time of inpatient admission.

CMS Pays CC/MCC DRG? NO

POA Indicator: U

Reason: Documentation insufficient to determine if the condition was present at the time of inpatient admission.

CMS Pays CC/MCC DRG? NO

POA Indicator: W

Reason: Clinically undetermined - unable to clinically determine whether the condition was present at the time of inpatient admission.

CMS Pays CC/MCC DRG? YES

POA Indicator: 1

Reason: Unreported/Not used - Exempt from POA reporting.

CMS Pays CC/MCC DRG? NO

Replacement Code

Z910110 replaces the following previously assigned ICD-10-CM code(s):

  • Z91.011 - Allergy to milk products

Code History

  • FY 2026 - Code Added, effective from 10/1/2025 through 9/30/2026