ICD-10-CM Z20-Z29 Code Range

Persons with potential health hazards related to communicable diseases (Z20-Z29) ICD-10-CM

The Z20–Z29 section covers persons with potential health hazards related to communicable diseases with 85 ICD-10-CM diagnosis codes, of which 65 are billable in fiscal year 2027. The section is organized into the 6 code ranges listed below.

✓ Built from the official CMS FY 2027 datasetEffective Oct 1, 2026 – Sep 30, 2027

Code Ranges

Diagnosis Codes

Billable Codes

Z20–Z29

Code Range

Code Range	Title	Codes	Billable
Z20	Contact with and (suspected) exposure to communicable diseases (Z20)	23	18
Z21	Asymptomatic human immunodeficiency virus [HIV] infection status (Z21)	1	1
Z22	Carrier of infectious disease (Z22)	26	20
Z23	Encounter for immunization (Z23)	1	1
Z28	Immunization not carried out and underimmunization status (Z28)	23	17
Z29	Encounter for other prophylactic measures (Z29)	11	8

Title

Codes

Billable

Z20

Contact with and (suspected) exposure to communicable diseases (Z20)

Z21

Asymptomatic human immunodeficiency virus [HIV] infection status (Z21)

Z22

Carrier of infectious disease (Z22)

Z23

Encounter for immunization (Z23)

Z28

Immunization not carried out and underimmunization status (Z28)

Z29

Encounter for other prophylactic measures (Z29)

About the Z20–Z29 Code Range

These codes address possible exposure to communicable diseases, infectious disease status, and immunization or other preventive measures.

Z20 separates suspected or known exposure by disease. Z21 identifies HIV infection without symptoms. Z22 separates carrier status by infection and also includes latent tuberculosis.

Z23 describes an immunization visit. Z28 separates immunizations not carried out by reason and also identifies underimmunization status. Z29 separates other preventive measures by type, including immunotherapy and fluoride administration.

FY 2027 changes: The FY 2027 ICD-10-CM update, effective October 1, 2026, revised the title of Z29.14.

Questions About This Page

How many codes are in the Z20-Z29 range?

The Z20-Z29 range contains 85 ICD-10-CM diagnosis codes in FY 2027. 65 of them are billable, and the rest are category headers that organize the section.

What conditions does Z20-Z29 cover?

The range covers persons with potential health hazards related to communicable diseases. The code ranges listed above break it into groups of related conditions, and each one links to its own page with the full code list.

Contact with and (suspected) exposure to communicable diseases (Z20)

Inside this range

Z20Contact with and (suspected) exposure to communicable diseases

Type 1 Excludes

A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

carrier of infectious disease Z22
diagnosed current infectious or parasitic disease -see Alphabetic Index

Type 2 Excludes

A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

personal history of infectious and parasitic diseases Z86.1

Open Z20 →

Asymptomatic human immunodeficiency virus [HIV] infection status (Z21)

Inside this range

Z21Asymptomatic human immunodeficiency virus [HIV] infection status

Inclusion Terms

These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.

HIV positive NOS

Code First

Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.