2026 ICD-10-CM Diagnosis Code Z20.818Contact with and (suspected) exposure to other bacterial communicable diseases

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

ICD-10-CM Z20.818
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Z20.818 is a billable ICD-10-CM diagnosis code for contact with and (suspected) exposure to other bacterial communicable diseases. 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. 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
Z20.818
Billable Status
Yes — Valid for Submission
Code Describes
Contact with and (suspected) exposure to other bacterial communicable diseases
Short Description
Contact w and exposure to oth bact communicable diseases
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 CodeZ20.818Contact with and (suspected) exposure to other bacterial communicable diseases

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z20.818.

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.

  • Brucellosis suspected
  • Diphtheria suspected
  • Exposure to anaerobic bacterial vaginosis
  • Exposure to bacterial vaginosis
  • Exposure to Bordetella pertussis
  • Exposure to Coccidioides immitis
  • Exposure to Francisella tularensis
  • Exposure to Gardnerella vaginalis
  • Exposure to Haemophilus ducreyi
  • Exposure to Haemophilus influenzae type b
  • Exposure to Klebsiella granulomatis
  • Exposure to Legionella
  • Exposure to Listeria moncytogenes
  • Exposure to Salmonella
  • Exposure to streptococcal pharyngitis
  • Exposure to Streptococcus
  • Exposure to Streptococcus pneumoniae
  • Exposure to Vibrio cholerae
  • Invasive group A beta-hemolytic streptococcal disease suspected
  • Legionella pneumonia suspected
  • Leprosy suspected
  • Lyme disease suspected
  • Pertussis suspected
  • Plague suspected
  • Scarlet fever suspected
  • Suspected soft tissue infection
  • Tetanus suspected
  • Typhoid fever suspected
  • Typhus suspected

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)
      • bacterial disease NEC
    • Contact(with)
      • communicable disease
        • bacterial NEC
    • Exposure(to)
      • bacterial disease NEC
    • Exposure(to)
      • communicable disease
        • bacterial NEC

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

Bacterial Infections

Bacteria are tiny organisms (living things) that have only one cell. Under a microscope, they look like balls, rods, or spirals. They can be found almost everywhere on Earth. There are lots of bacteria in and on your body. In fact, your body has about 10 times more bacteria cells than human cells.

The full article covers:

  • What are bacteria?
  • How do bacterial infections spread?
  • What are the treatments for bacterial infections?
  • Can bacterial infections be prevented?

Read the full article at MedlinePlus

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

Convert Z20.818 to ICD-9-CMHistory

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

ICD-9-CM
V01.89 Communic dis contact NEC
Approximate The match is approximate rather than exact.

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 Z20.818Overview

Is Z20.818 a billable code?

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

Can Z20.818 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because contact with and (suspected) exposure to other bacterial communicable diseases 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 Z20.818?

Under the General Equivalence Mappings, contact with and (suspected) exposure to other bacterial communicable diseases converts to ICD-9-CM V01.89 (communic dis contact NEC). The mapping is approximate, so confirm the match fits the documentation.