2024 ICD-10-CM Diagnosis Code Z20.821

Contact with and (suspected) exposure to Zika virus

ICD-10-CM Code:
Z20.821
ICD-10 Code for:
Contact with and (suspected) exposure to Zika virus
Is Billable?
Yes - Valid for Submission
Code Navigator:

Code Classification

  • Factors influencing health status and contact with health services
    (Z00–Z99)
    • Persons with potential health hazards related to communicable diseases
      (Z20-Z29)
      • Contact with and exposure to communicable diseases (Z20)
        (suspected)

Z20.821 is a billable diagnosis code used to specify a medical diagnosis of contact with and (suspected) exposure to zika virus. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024. 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.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Exposure to Zika virus

Clinical Classification

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).

Code Edits

The Medicare Code Editor (MCE) detects and reports errors in the coding of claims data. The following ICD-10-CM Code Edits are applicable to this code:

  • 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)

Z20.821 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 IndicatorReason for CodeCMS will pay the CC/MCC DRG?
YDiagnosis was present at time of inpatient admission.YES
NDiagnosis was not present at time of inpatient admission.NO
UDocumentation insufficient to determine if the condition was present at the time of inpatient admission.NO
WClinically undetermined - unable to clinically determine whether the condition was present at the time of inpatient admission.YES
1Unreported/Not used - Exempt from POA reporting. NO

Replacement Code

Z20821 replaces the following previously assigned ICD-10-CM code(s):

  • Z20.828 - Contact w and exposure to oth viral communicable diseases

Patient Education


Zika Virus

Zika is a virus that is spread mostly by mosquitoes. A pregnant mother can pass it to her baby during pregnancy or around the time of birth. It can spread through sexual contact. There have also been reports that the virus has spread through blood transfusions. There have been outbreaks of Zika virus in the United States, Africa, Southeast Asia, the Pacific Islands, parts of the Caribbean, and Central and South America.

Most people who get the virus do not get sick. One in five people do get symptoms, which can include a fever, rash, joint pain, and conjunctivitis (pink eye). Symptoms are usually mild, and start 2 to 7 days after being bitten by an infected mosquito.

A blood test can tell whether you have the infection. There are no vaccines or medicines to treat it. Drinking lots of fluids, resting, and taking acetaminophen might help.

Zika can cause microcephaly (a serious birth defect of the brain) and other problems in babies whose mothers were infected while pregnant. The Centers for Disease Control and Prevention recommends that pregnant women do not travel to areas where there is a Zika virus outbreak. If you do decide to travel, first talk to your doctor. You should also be careful to prevent mosquito bites:

  • Use insect repellent
  • Wear clothes that cover your arms, legs, and feet
  • Stay in places that have air conditioning or that use window and door screens

Centers for Disease Control and Prevention


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019