CDC Classification System for HIV Infection in Adults and Adolescents

This classification system is how the United States agency, the Centers for Disease Control and Prevention (CDC) classifies HIV disease and infection. This is to allow the government to handle epidemic statistics and define who receives US government assistance. In 1993, the CDC added pulmonary tuberculosis, recurrent pneumonia, and invasive cervical cancer to the list of clinical conditions in the AIDS surveillance case definition published in 1987 and expanded the AIDS surveillance case definition to include all HIV-infected persons with CD4+ T-lymphocyte counts of less than 200 cells/uL or a CD4+ percentage of less than 14. Considerable variation exists in the relative risk of death following different AIDS defining clinical conditions.

According to the US CDC definition, one has AIDS if he/she is infected with HIV and present with one of the following:

A CD4+ T-cell count below 200 cells/µl (or a CD4+ T-cell percentage of total lymphocytes of less than 14%).

or he/she has one of the following defining illnesses:

• Candidiasis of bronchi, trachea, or lungs
• Candidiasis esophageal
• Cervical cancer (invasive)
• Coccidioidomycosis, disseminated or extrapulmonary
• Cryptococcosis, extrapulmonary
• Cryptosporidiosis, chronic intestinal for longer than 1 month
• Cytomegalovirus disease (other than liver, spleen or lymph nodes)
• Encephalopathy (HIV-related)
• Herpes simplex: chronic ulcer(s) (for more than 1 month); or bronchitis, pneumonitis, or esophagitis
• Histoplasmosis, disseminated or extrapulmonary
• Isosporiasis, chronic intestinal (for more than 1 month)
• Kaposi's sarcoma
• Lymphoma Burkitt's, immunoblastic or primary brain
• Mycobacterium avium complex
• Mycobacterium, other species, disseminated or extrapulmonary
• Pneumocystis carinii pneumonia
• Pneumonia (recurrent)
• Progressive multifocal leukoencephalopathy
• Salmonella septicemia (recurrent)
• Toxoplasmosis of the brain
• Tuberculosis
• Wasting syndrome due to HIV

People who are not infected with HIV may also develop these conditions; this does not mean they have AIDS. However, when an individual presents laboratory evidence against HIV infection, a diagnosis of AIDS is ruled out unless the patient has not:

• undergone high-dose corticoid therapy or other immunosuppressive/cytotoxic therapy in the three months before the onset of the indicator disease
• OR been diagnosed with Hodgkin's disease, non-Hodgkin's lymphoma, lymphocytic leukemia, multiple myeloma, or any cancer of lymphoreticular or histiocytic tissue, or angioimmunoblastic lymphoadenopathy
• OR a genetic immunodeficiency syndrome atypical of HIV infection, such as one involving hypogamma globulinemia

AND

• the individual has had Pneumocystis carinii pneumonia
• OR one of the above defining illnesses AND a CD4+ T-cell count below 200 cells/µl (or a CD4+ T-cell percentage of total lymphocytes of less than 14%).

References

• CDC. Revision of the CDC surveillance case definition for acquired immunodeficiency syndrome. MMWR 1987;36:1-15S.
• CDC. 1993 Revised Classification System for HIV Infection and Expanded Surveillance Case Definition for AIDS Among Adolescents and Adults
• AIDS info
• Disease progression and survival following specific AIDS-defining conditions: a retrospective cohort study of 2048 HIV-infected persons in London.
• AIDS.gov - The U.S. Federal Domestic HIV/AIDS Resource
• HIVtest.org - Find an HIV testing site near you