2026 ICD-10-CM Diagnosis Code Z77.120Contact with and (suspected) exposure to mold (toxic)

ICD-10-CM Codes›Z00–Z99›Z77-Z99›suspected

ICD-10-CM Z77.120
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Z77.120 is a billable ICD-10-CM diagnosis code for contact with and (suspected) exposure to mold (toxic). It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. Coders also document this condition as allergic rhinitis caused by mold. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified status.

Code Identity

ICD-10-CM Code
Z77.120
Billable Status
Yes — Valid for Submission
Code Describes
Contact with and (suspected) exposure to mold (toxic)
Short Description
Contact with and (suspected) exposure to mold (toxic)
Same as the full description in the CMS dataset.
Parent Code
Z77.12
Contact with and (suspected) exposure to hazards in the physical environment

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ77-Z99Persons with potential health hazards related to family and personal history and certain conditions influencing health status
CategorysuspectedOther contact with and exposures hazardous to health (Z77)
This CodeZ77.120Contact with and (suspected) exposure to mold (toxic)

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z77.120.

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

Z77.120 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Allergic rhinitis caused by mold
  • Environment contains mold
  • Exposure to mold
  • Mold in residence
  • Mold on bedding in home
  • Mold on clothing in home
  • Mold on surfaces in home

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Contact(with)
      • mold (toxic)
    • Exposure(to)
      • mold (toxic)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR FAC025
Other specified status
Default principal diagnosis: inpatient No · outpatient Yes

Patient EducationClinical

Molds

Molds are fungi that can be found both outdoors and indoors. They grow best in warm, damp and humid conditions. If you have damp or wet spots in your house, you will probably get mold.

Read the full article at MedlinePlus

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

Convert Z77.120 to ICD-9-CMHistory

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

ICD-9-CM
V87.31 Contact/exposure mold
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Z77.120Overview

Is Z77.120 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report contact with and (suspected) exposure to mold (toxic) on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can Z77.120 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because contact with and (suspected) exposure to mold (toxic) describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z77.120 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 contact with and (suspected) exposure to mold (toxic) on inpatient claims.

What is the ICD-9 equivalent of Z77.120?

Under the General Equivalence Mappings, contact with and (suspected) exposure to mold (toxic) converts to ICD-9-CM V87.31 (contact/exposure mold). The mapping is a direct match.