Skip to main content

HIV Disease Classification

Revised Surveillance Case Definition or HIV Infection – US, 2014#

StageLaboratory evidence*Clinical evidence
Stage 0Inferred from a negative or indetermined HIV test result within 180 days of the first confirmed positive resultNone required (but no AIDS-defining condition)
Stage 1Laboratory confirmation of HIV infection and
Age >6 years: CD4+ T-lymphocyte count of ≥500 cells/μL, or >26%;
Age 1-5 years: CD4+ T-lymphocyte count of ≥1000 cells/μL, or >30%;
Age <1 year: CD4+ T-lymphocyte count of ≥1500 cells/μL, or >34%		None required (but no AIDS-defining condition)
Stage 2Laboratory confirmation of HIV infection and
Age >6 years: CD4+ T-lymphocyte count of 200-499 cells/μL, or 14-25%;
Age 1-5 years: CD4+ T-lymphocyte count of 500-999 cells/μL, or 22-29%;
Age <1 year: CD4+ T-lymphocyte count of 750-1499 cells/μL, or 26-33%		None required (but no AIDS-defining condition)
Stage 3
(AIDS)		Laboratory confirmation of HIV infection and
Age >6 years: CD4+ T-lymphocyte count of <200 cells/μL, or <14%;
Age 1-5 years: CD4+ T-lymphocyte count of <500 cells/μL, or <22%;
Age <1 year: CD4+ T-lymphocyte count of <750 cells/μL, or <26%%		or documentation of an AIDS-defining condition with laboratory confirmation of HIV infection)†
Stage unknownLaboratory confirmation of HIV infection and no information on CD4+ T-lymphocyte count or % and no information on the presence of an AIDS-defining condition (with laboratory confirmation of HIV infection)

Criteria for a confirmed case can be met by either laboratory or clinical evidence; however laboratory evidence (CD4 cell count level) is preferred. CD4 T-lymphocyte percentage is used only when the corresponding CD4 T-lymphocyte count is unknown.

*The CD4+ T-lymphocyte percentage is the percentage of total lymphocytes.

†Documentation of an AIDS-defining condition supersedes a CD4+ T-lymphocyte count of >200 cells/μL.

Only Stage 3 or the presence of an AIDS-defining condition is recognized as AIDS.

Related Pages#

References/Websites#