2027 ICD-10-CM Diagnosis Code Z20.820Contact with and (suspected) exposure to varicella

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

ICD-10-CM Z20.820
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z20.820 is a billable ICD-10-CM diagnosis code for contact with and (suspected) exposure to varicella. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 795, 951. Coders also document this condition as exposure to varicella. 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
Z20.820
Billable Status
Yes — Valid for Submission
Code Describes
Contact with and (suspected) exposure to varicella
Short Description
Contact with and (suspected) exposure to varicella
Same as the full description in the CMS dataset.
Parent Code
Z20.82
Contact with and (suspected) exposure to other viral 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 CodeZ20.820Contact with and (suspected) exposure to varicella

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Exposure to varicella

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z20.820: 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.

From Z20 Contact with and (suspected) exposure to communicable diseases applies to 18 codes
  • carrier of infectious disease (Z22.-)
  • diagnosed current infectious or parasitic disease -see Alphabetic Index

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.

From Z20 Contact with and (suspected) exposure to communicable diseases applies to 18 codes
  • personal history of infectious and parasitic diseases (Z86.1-)

Notes

General instructions on how these codes are used.

From Chapter 21 (Z00-Z99) Factors influencing health status and contact with health services applies to 1,425 codes
  • 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 Z20.820, its category, or a range that includes it.

Excludes2 2

These codes carry an Excludes2 note naming Z20.820: 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 health
    contact with and (suspected) exposure to communicable diseases (Z20.-) names Z20.-, which includes this code
  • Z83 Family history of other specific disorders
    contact 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.

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 Yes · outpatient Yes

Patient EducationClinical

Chickenpox

Chickenpox is an infection caused by the varicella-zoster virus. Most cases are in children under age 15, but older children and adults can get it. It spreads very easily from one person to another.

Read the full article at MedlinePlus

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

Convert Z20.820 to ICD-9-CMHistory

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

ICD-9-CM
V01.71 Varicella contact/exp
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Z20.820Overview

What is the ICD-10 code for contact with and (suspected) exposure to varicella?

The ICD-10-CM code for contact with and (suspected) exposure to varicella is Z20.820 (sometimes written as Z20820). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Z20.820 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report contact with and (suspected) exposure to varicella on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z20.820 group to?

When contact with and (suspected) exposure to varicella is the principal diagnosis on an inpatient stay, it groups to MS-DRG 951, 795, with relative weights from 0.2022 to 0.5574 depending on complications. Higher weights mean higher Medicare reimbursement.

Can Z20.820 be reported with a code from Z22?

Not as a rule. The Excludes1 note at Z20, which applies to Z20.820, 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).

What is the ICD-9 equivalent of Z20.820?

Under the General Equivalence Mappings, contact with and (suspected) exposure to varicella converts to ICD-9-CM V01.71 (varicella contact/exp). The mapping is a direct match.