The only way to know for sure that you have been infected with HIV is to have a blood test.

Testing for HIV infection

Because it takes some time for symptoms to appear following HIV infection, it is primarily detected by a blood test for antibodies (disease-fighting proteins) that the infected person produces in response to the virus entering the body. Antibody levels generally do not reach levels high enough to be detected until one to three months after infection, and it may take up to six months for levels to become high enough to show up in standard blood tests. The change from a negative test for antibodies to a positive one is called seroconversion.

If you feel you have been exposed to HIV, you should be tested as soon as you are likely to develop antibodies. Early testing will enable you to receive appropriate treatment at a time when you are most able to slow the progress of the disease and prevent opportunistic infections. Early testing will also alert you to avoid high-risk behaviors that could spread HIV to other people.

Testing is done in most doctors' offices or health clinics and should be accompanied by counseling. Many sites allow you to be tested anonymously if you are concerned about confidentiality.

Two different tests (ELISA and Western blot) are used. If it is highly likely that you are infected, but both tests are negative, a doctor may test for the presence of the virus itself in your blood. You may then be asked to return at a later date for repeat testing, when antibodies are more likely to be present.

Babies born to mothers infected with HIV may or may not be infected, but they all carry their mothers' antibodies for several months. If these babies have no symptoms, a diagnosis using standard tests cannot be made until the baby is at least 15 months old. By then, they will no longer have the mother's antibodies and will have produced their own, if they are infected. New techniques now make it possible to determine HIV infection more accurately in infants 3 months to 15 months old. Further tests are now being studied that may enable diagnosis in babies younger than 3 months.

Who should get tested?

Ideally, anyone at risk for AIDS because of risky behavior (unprotected sex or abuse of injected drugs) should be tested for HIV infection. However, a recent survey of more than 13,000 adults found that an "alarmingly high" proportion (more than 60% of those at highest risk) had not been tested.

Slightly lest than one third (30%) of adults seek testing solely to find out if they are infected. Other reasons for testing include: hospitalization for surgery (12%); application for insurance (16%); military induction (7%); referral by a doctor, health department, or sexual partner (7%); or for immigration-related reasons (4%).³ The ethics of such "mandatory testing" has become a source of concern among AIDS activists.

Symptoms and complications

Many people have no symptoms when they first become infected with HIV, and others may have a flu-like illness within a month or two after exposure to the virus. They may have fever, headache, fatigue, and enlarged lymph nodes (organs of the immune system located in the neck and groin). These symptoms usually disappear after one week to a month, and are often mistaken for flu or another viral infection.

As the immune system loses its effectiveness, several complications occur. One of the first such symptoms is enlargement of the lymph nodes lasting more than three months. Other symptoms appearing months or years after HIV infection include lack of energy, weight loss, frequent fevers or sweating, persistent or frequent yeast infections (oral or vaginal), persistent skin rashes or flaky skin, pelvic inflammatory disease that does not respond to treatment, or short-term memory loss. Some people develop frequent and severe herpes infections (causing mouth, genital, or anal sores) or a painful nerve disease called shingles. Children may show delayed development or failure to thrive.

Opportunistic infections common in people with AIDS cause such symptoms as coughing, shortness of breath, seizures, dementia, severe and persistent diarrhea, fever, vision loss, severe headaches, wasting, extreme fatigue, nausea, vomiting, lack of coordination, coma, abdominal cramps, or difficult or painful swallowing.

Children with AIDS may get the same opportunistic infections as adults, but they also experience severe forms of bacterial infections common in children, such as conjunctivitis (pink eye), ear infections, and tonsillitis.

People with AIDS may develop various cancers, such as Kaposi's sarcoma or cancers of the immune system (lymphomas). Kaposi's sarcoma appears in light-skinned people as round brown, reddish, or purple spots that develop in the skin or in the mouth. In dark-skinned people, the spots are darker (more pigmented). These cancers tend to be more aggressive and difficult to treat in people with AIDS.

Some people with HIV develop sever loss of appetite (anorexia) which may lead to wasting syndrome: major weight loss, chronic diarrhea or weakness, and fever lasting at least 30 days. Diarrhea caused by illness can lead to or worsen wasting syndrome.

How to get tested for HIV infection

Testing centers are available in every major city and region of the US. Check your local telephone directory for a local listing. You may also contact the national organizations listed in the Resources section of this Condition Forum.

Viral load testing

A viral load test measures the amount of HIV in your blood. The result is given as the number of HIV RNA copies in 1 ml (about one-quarter teaspoon) of your blood. RNA is part of HIV, and each HIV virus has two copies of RNA. Two types of viral load tests are in common use. One is called a PCR test, and the other is a bDNA test.

The test is relatively new and not very precise. Also, any infections, such as the flu, can make your viral load go up significantly for quite a while. Nevertheless, doctors use the viral load test for two reasons: to predict the progression of disease and to see how well anti-HIV drugs are working.

You may have to insist on a viral load test when you want it. Besides noting the result, be sure to ask which test was used, since the results of one test cannot be compared directly with the results of the other.

How do I know if I have AIDS?

HIV Home Testing Kits

The Federal Trade Commission issued a June 1999 Consumer Alert regarding the use of HIV Testing kits advertised and sold on the Internet for self diagnosis at home. FTC - sponsored testing of these kits have shown, in every case, a negative result when used on a known HIV-positive sample - that is, when they should have shown a positive result. Using one of these kits could give a person who might be infected with HIV the false impression that he or she is not infected. Some Internet sites falsely state or imply that the kits have been approved by the World Health Organization or the U.S. Food and Drug Administration. However, the FDA has approved one HIV home collection test system for sale in the U.S. It is called the Home Access Express HIV-1 Test System and allows consumers to collect the sample in the privacy of their home and then mail it to a testing facility for analysis. The FTC explains that safe, reliable HIV testing can be done only through a medical professional or a clinic, or through use of the Home Access Express HIV-1 Test System. Additional information about HIV home-use test kits can be found at the FDA website (http://www.fda.gov/) and by calling the CDC National Prevention Information Network at 1-800-458-5231.