ELISA Test, ELISA, which stands for enzyme-linked immunosorbent assay , is used to detect HIV infection . If an ELISA test is positive , the Western blot test is usually administered to confirm the diagnosis . HIV is the virus that causes AIDS . This virus has a long incubation period before it starts to attack the immune system (10 years). The immune system is the human body’s natural defence mechanism, hence HIV can make it harder for the patient to fight off infections and diseases. HIV demolishes a particular type of WBC (White Blood Cells) and the T-helper cells. This virus also makes copies of itself inside these cells. T-helper cells are also known as CD4 cells.