2027 ICD-10-CM Diagnosis Code Z20.810Contact with and (suspected) exposure to anthrax
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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 795, 951. 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
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for Z20.810.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Anthrax suspected
- Exposure to Bacillus anthracis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to Z20.810: its own notes plus those printed at Z20 and Chapter 21. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Notes
General instructions on how these codes are used.
- Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
- (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
- (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name Z20.810, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming Z20.810: its condition is not part of those codes, and both may be reported when the patient has both.
- Z77 Other contact with and (suspected) exposures hazardous to healthcontact with and (suspected) exposure to communicable diseases (Z20.-) names Z20.-, which includes this code
- Z83 Family history of other specific disorderscontact with and (suspected) exposure to communicable disease in the family (Z20.-) names Z20.-, which includes this code
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Contact (with) See Also: Exposure (to);
anthrax Z20.810
Exposure (to) See Also: Contact, with; T75.89
anthrax Z20.810
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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.
Code HistoryHistory
Questions About Z20.810Overview
What is the ICD-10 code for contact with and (suspected) exposure to anthrax?
The ICD-10-CM code for contact with and (suspected) exposure to anthrax is Z20.810 (sometimes written as Z20810). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
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, 2026 through September 30, 2027.
What MS-DRG does Z20.810 group to?
On inpatient claims, contact with and (suspected) exposure to anthrax maps to MS-DRG 951, 795, with relative weights from 0.2022 to 0.5574 depending on complications. Higher weights mean higher Medicare reimbursement.
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.
Can Z20.810 be reported with a code from Z22?
Not as a rule. The Excludes1 note at Z20, which applies to Z20.810, lists "carrier of infectious disease (Z22.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
