Diagnosis
The diagnosis of HIV has two stages. In the first stage, ELISA tests are used to detect whether or not the virus is present in the blood. This test is also helpful to screen for HIV in high-risk patients. Only when this test is positive, the diagnosis needs to be confirmed with a Western Blot assay, which is more specific. The results can be positive or negative, but they are sometimes indeterminate, and the exam needs to be repeated.
After confirming a case of HIV or AIDS, the next step would be differentiating what species of HIV is infecting the patient, his viral load, and his CD4 count. All of this is useful to know the stage of the disease and what to do next.
Several evaluations and laboratory studies can be performed in patients depending on their condition, symptoms, and likely infections.