Diagnosis Your doctor will ask about possible HIV risk factors,

Diagnosis

Your doctor will ask about possible HIV risk factors, such as previous sexual partners, intravenous drug use, blood transfusion and occupational exposure to blood. Your doctor will ask about a variety of symptoms, such as fever, weight loss, muscle and joint aches, fatigue and headache, and about medical problems you may have had, such as skin rashes or infections, sinusitis, pneumonia and yeast infections. This typically is followed by a complete physical examination. Your doctor will look for a thick, white coating on your tongue that may be thrush (infection with Candida fungus), skin abnormalities such as Kaposi's sarcoma or recurrent infections and other abnormalities that suggest the diagnosis of AIDS.

HIV testing can be done in your doctor's office or in an anonymous clinic. Your doctor will confirm the diagnosis of HIV infection through blood tests. The initial screening test is called enzyme linked immunosorbent assay (ELISA). It detects disease-fighting proteins in your immune system (antibodies) specific to HIV. A Western blot test, which also measures the body's response to HIV, is more accurate, and is done to confirm the diagnosis. Neither the ELISA nor Western blot is accurate immediately after exposure to the HIV virus. It can take a few months for these tests to become positive.

The period between infection with HIV and the development of positive test results on ELISA and Western blot is called the window period. This term refers to the window of time between getting the HIV infection and the ability to detect the body's response to infection with one of these two tests. If the test results are positive, another test, called the HIV RNA blood test, can measure the amount of HIV virus in the blood (viral load). To confirm the diagnosis of AIDS, your doctor will order a blood test for CD4 cell count. A count less than 200 cells per cubic milliliter of blood indicates AIDS. You also may have tests to diagnose AIDS-related conditions, including opportunistic infections, brain illness, a tumor, body wasting or lung illness, depending on your symptoms.