CDC classification system for HIV infection


The CDC Classification System for HIV Infection is the medical classification system used by the United States Centers for Disease Control and Prevention to classify HIV disease and infection. The system is used to allow the government to handle epidemic statistics and define who receives US government assistance.

In adults and adolescents

This classification system is how the United States agency, the Centers for Disease Control and Prevention 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
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:
  • undergone high-dose corticoid therapy or other immunosuppressive/cytotoxic therapy in the three months before the onset of the indicator diseaseOR been diagnosed with Hodgkin's disease, non-Hodgkin's lymphoma, lymphocytic leukemia, multiple myeloma, or any cancer of lymphoreticular or histiocytic tissue, or angioimmunoblastic lymphoadenopathyOR a genetic immunodeficiency syndrome atypical of HIV infection, such as one involving
AND
  • the individual has had Pneumocystis carinii pneumoniaOR one of the above defining illnesses AND a CD4+ T-cell count below 200 cells/μl.

In children

Due to the additional knowledge of the progression of HIV disease among children, a revised classification system for HIV infection in children was developed in 1994 that replaced the pediatric HIV classification system that was published in 1987. A child for the purposes of the CDC is an individual of less than 13 years of age. Standard anti-HIV IgG antibody tests cannot be used to reliably indicate a child's infection status before 18 months of age, so viral antigen tests are used.
In the new system, HIV-infected children are classified into mutually exclusive categories according to three parameters:
This classification system reflects the stage of the child's disease, establishes mutually exclusive classification categories, and balances simplicity and medical accuracy in the classification process. This document also describes revised pediatric definitions for two acquired immunodeficiency syndrome-defining conditions.
When an infant is born to an HIV-infected mother, diagnosis of an HIV infection is complicated by the presence of maternal anti-HIV IgG antibody, which crosses the placenta to the fetus. Indeed, virtually all children born to HIV-infected mothers are HIV-antibody positive at birth, although only 15%-30% are actually infected.

Category N: Not symptomatic

Children who have no signs or symptoms considered to be the result of HIV
infection or who have only one of the conditions listed in Category A.

Category A: Mildly symptomatic

Children with two or more of the conditions listed below but none of the conditions listed in Categories B and C.

Category B: Moderately symptomatic

Children who have symptomatic conditions other than those listed for Category
A or C that are attributed to HIV infection. Examples of conditions in clinical
Category B include but are not limited to:

Category C: Severely symptomatic