CD4 cell counts are used in the CDC staging system to track the development of HIV in an effort to manage the epidemic. A patient is diagnosed with AIDS once the CD4 count of such a patient falls below 200mm3 (or the CD4 percentage is less than 14%), or certain HIV conditions known as opportunistic infections are diagnosed. Opportunistic infections include malaria and candidiasis. Although such conditions are not automatically fatal to a person without HIV, they are the primary causes of death in AIDS patients. Consequently, even though a patient’s CD4 count may not have breached the 200mm3 threshold upon the first instance of the occurrence of an opportunistic illness or condition, such a patient shall be diagnosed with AIDS. For a better understanding of the CD4 staging process, the following table is helpful:
|Clinical Category A||Clinical Category B||Clinical Category C|
|CD4 Cell Categories||Asymptomatic, Acute HIV, or Persistent Generalized Lymphadenopathy||Symptomatic Conditions, neither A nor C||AIDS-Indicator Conditions|
|≥500 cells mm3||A1||B1||C1|
|200-499 cells mm3||A2||B2||C2|
|<200 cells mm3||A3||B3||C3|
The basis of this staging test is that diagnosis or labeling occurs based on either the lowest documented CD4 count or the past diagnosis of HIV-related infections. Consequently, if a patient once had an asymptomatic HIV-related condition in B such as thrush but is presently asymptomatic, he or she shall remain in B regardless of any subsequent developments. Meanwhile, categories A3, B3, and C3 are considered AIDS, even though the patients may not have depicted the symptoms that are directly reflective of AIDS. The criterion is that their CD4 count is below the established threshold of 200mm3. Such patients have been prescribed Highly Active Antiretroviral Treatments (HAART). In fact, they may yet live a number of years. However, they are fatally vulnerable to common infections.