Z20.821 Contact with and (suspected) exposure to Zika virus

The ICD-10-CM code for Contact with and (suspected) exposure to Zika virus is Z20.821 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

21: Factors influencing health status and contact with health services (Z00-Z99)

Section

Z20-Z29: Persons with potential health hazards related to communicable diseases (Z20-Z29)

Category Z20

23 codes (18 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to Z20.821:

• Exposure (to) › Zika virus
• Contact (with) › Zika virus
• Exposure (to) › communicable disease › Zika virus
• Contact (with) › communicable disease › Zika virus

U.S. Hospital Utilization

• An estimated 260 U.S. inpatient stays in 2023 included Z20.821 among the documented diagnoses.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Zika—code only confirmed cases; suspected/possible/probable not coded

f. Zika virus infections 1) Code only confirmed cases Code only a confirmed diagnosis of Zika virus (A92.5, Zika virus disease) as documented by the provider. This is an exception to the hospital inpatient guideline Section II, H. In this context, “confirmation” does not require documentation of the type of test performed; the provider’s diagnostic statement that the condition is confirmed is sufficient. This code should be assigned regardless of the stated mode of transmission. If the provider documents "suspected", "possible" or "probable" Zika, do not assign code A92.5. Assign a code(s) explaining the reason for encounter (such as fever, rash, or joint pain) or Z20.821, Contact with and (suspected) exposure to Zika virus.

Used with any code in range A00.0-T88.9, Z00-Z99

1) Used with any code in the range of A00.0-T88.9, Z00-Z99 An external cause code may be used with any code in the range of A00.0-T88.9, Z00-Z99, classification that represents a health condition due to an external cause. Though they are most applicable to injuries, they are also valid for use with such things as infections or diseases due to an external source, and other health conditions, such as a heart attack that occurs during strenuous physical activity.

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)