2026 ICD-10-CM Diagnosis Code Z20.810Contact with and (suspected) exposure to anthrax

ICD-10-CM Codes›Z00–Z99›Z20-Z29›suspected

ICD-10-CM Z20.810
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Z20.810 is a billable ICD-10-CM diagnosis code for contact with and (suspected) exposure to anthrax. 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. Coders also document this condition as anthrax suspected. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Exposure, encounters, screening or contact with infectious disease.

Code Identity

ICD-10-CM Code
Z20.810
Billable Status
Yes — Valid for Submission
Code Describes
Contact with and (suspected) exposure to anthrax
Short Description
Contact with and (suspected) exposure to anthrax
Same as the full description in the CMS dataset.
Parent Code
Z20.81
Contact with and (suspected) exposure to other bacterial communicable diseases

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ20-Z29Persons with potential health hazards related to communicable diseases
CategorysuspectedContact with and exposure to communicable diseases (Z20)
This CodeZ20.810Contact with and (suspected) exposure to anthrax

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z20.810.

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.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Anthrax suspected
  • Exposure to Bacillus anthracis

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)
      • anthrax
    • Exposure(to)
      • anthrax

Clinical ClassificationClinical

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

CCSR FAC016
Exposure, encounters, screening or contact with infectious disease
Default principal diagnosis: inpatient No · outpatient Yes

Patient EducationClinical

Anthrax

Anthrax is a disease caused by Bacillus anthracis, a germ that lives in soil. Many people know about it from the 2001 bioterror attacks. In the attacks, someone purposely spread anthrax through the U.S. mail. This killed five people and made 22 sick.

Read the full article at MedlinePlus

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

Convert Z20.810 to ICD-9-CMHistory

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

ICD-9-CM
V01.81 Contact/exposure-anthrax
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 Z20.810Overview

Is Z20.810 a billable code?

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

Can Z20.810 be a principal diagnosis?

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

What is the ICD-9 equivalent of Z20.810?

Under the General Equivalence Mappings, contact with and (suspected) exposure to anthrax converts to ICD-9-CM V01.81 (contact/exposure-anthrax). The mapping is a direct match.