Z21Asymptomatic human immunodeficiency virus [HIV] infection status

Z21 is the ICD-10-CM diagnosis code for Asymptomatic human immunodeficiency virus [HIV] infection status. It belongs to block Z20-Z29 (persons with potential health hazards related to communicable diseases) and chapter 21 (factors influencing health status and contact with health services). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Don't report Z21 together with the conditions in its Excludes1 note: acquired immunodeficiency syndrome (B20), contact with human immunodeficiency virus [HIV] (Z20.6), exposure to human immunodeficiency virus [HIV] (Z20.6), human immunodeficiency virus [HIV] disease (B20) and 1 more.

Code first: Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium, if applicable (O98.7-).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 865 (Viral Illness with MCC, relative weight 1.3485) and DRG 866 (Viral Illness without MCC, relative weight 0.8692), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

When it is the principal diagnosis, Medicare considers it a questionable reason for an inpatient admission, so claims may be reviewed.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as V08 (Asymptomatic human immunodeficiency virus [HIV] infection status).