FY2027 ICD-10-CM reference
Z21: Asymptomatic human immunodeficiency virus [HIV] infection status
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Asymptomatic human immunodeficiency virus [HIV] infection status. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Billable code. Verified against the official FY2027 order file.
FY2027 Tabular instructions
Instructions below include applicable chapter, section and parent-code notes. Each note identifies where it appears in the official source.
Instructional note
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:
Source: Z00-Z99 (chapter, inherited).
Instructional note
(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.
Source: Z00-Z99 (chapter, inherited).
Instructional note
(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: Z00-Z99 (chapter, inherited).
Instructional note
HIV positive NOS
Source: Z21 (category, direct).
Code first
Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium, if applicable (O98.7-)
Source: Z21 (category, direct).
Excludes1
acquired immunodeficiency syndrome (B20)
Source: Z21 (category, direct).
Excludes1
contact with human immunodeficiency virus [HIV] (Z20.6)
Source: Z21 (category, direct).
Excludes1
exposure to human immunodeficiency virus [HIV] (Z20.6)
Source: Z21 (category, direct).
Excludes1
human immunodeficiency virus [HIV] disease (B20)
Source: Z21 (category, direct).
Excludes1
inconclusive laboratory evidence of human immunodeficiency virus [HIV] (R75)
Source: Z21 (category, direct).
Compare the FY2027 additions, removals and billable-status changes
What does Z21 mean in FY2027?
The official ICD-10-CM descriptor is Asymptomatic human immunodeficiency virus [HIV] infection status. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is Z21 billable in FY2027?
The FY2027 order file marks Z21 as billable. Check the complete Tabular instructions and documentation before assigning it.
Does Z21 map to an HCC?
In the CMS 2027 Initial ICD-10-CM Mappings (payment year 2027, 2026 dates of service), Z21 maps to CMS-HCC V28 HCC 1 (HIV/AIDS). For 2027 dates of service, CMS has not yet published the payment year 2028 mappings. Under the PY2026 CMS mapping; CMS 2027 initial file unchanged: ESRD HCC 1; RxHCC HCC 1. Coefficients for these models are pending verification for payment year 2027. HHS-HCC: HCC 1 under the HHS-HCC 2026 benefit year mapping (no RAF; HHS-HCC weights vary by metal level). CMS-HCC V24: not used for payment year 2027 Medicare Advantage payment (CMS CY 2027 Rate Announcement). The PACE mapping is still pending verification for FY2027.
Source: CMS FY2027 ICD-10-CM order file. Payment model: CMS CY 2027 Rate Announcement. Read the FY2027 Official Guidelines.
Review the FY2026 April edition