All of the antibody tests are based on ELISA and Western Blot techniques. All of these tests are subject to the same window period (up to 6 months). For more information on the basics of antibody tests (including window periods, accuracy, etc.), read the following posts in the Frequently Asked Questions Area of this website:
What makes each of these tests different, are the body fluids used for testing, and how the specimens are collected. Each type of antibody test has it's own advantages and disadvantages. The following reviews the different types of antibody tests available.
"Traditional" blood antibody tests: These tests were first developed in 1985 and were the first HIV tests available. If antibodies are being produced in the body, these tests can easily find them. These tests are widely available at numerous clinics and doctors offices, and are very inexpensive (sometimes even free). However there are certain disadvantages with these tests. Many people do not like having their blood drawn. There is the risk of healthcare workers sticking themselves with the needles, and being exposed to potentially infected blood. In addition, people who have hemophilia, or people taking medications that affect bleeding, should consider taking saliva or urine based tests (see below), since taking blood may cause bleeding problems in these patients.
Home blood antibody tests: These tests are very similar to the "traditional" blood tests, except the blood samples are collected at home, and then mailed to a lab for analysis. Just like the traditional blood tests, people who have hemophilia, people taking medications affecting bleeding, or people who do not like getting stuck for a blood sample, should consider taking saliva or urine based tests (see below). For more information on home testing, see the posting How accurate are the home HIV tests.
Rapid antibody tests (for example SUDS tests): A SUDS test is an antibody test that can be done right in the doctor's office. This test also uses blood. The staff at the doctors office must be specially trained in how to do this test. Results can come back in as fast as 15-30 minutes. If the test is negative, you will know in 15-30 minutes. If it is positive, you will still have to take the standard ELISA and Western Blot tests for confirmation. This is because the SUDS test can occasionally show a false positive result. In other words, a positive SUDS test alone does not necessarily mean the person is HIV positive. That is why the standard ELISA and Western Blot tests must still be done if the SUDS test comes up positive. Since the standard ELISA/Western Blot tests can take about a week for results to come in, the person would have to wait a week for confirmation, knowing they might be positive. This waiting time can be a difficult emotional experience. So if a person tests negative on a SUDS test, they will know in about 15-30 minutes. If they test positive, the waiting time to get confirmation of the results can be mentally very difficult. The SUDS test is also generally more expensive than the standard ELISA/Western Blot tests. Most places presently do not offer SUDS tests, or similar rapid antibody tests. Remember, what is rapid about these tests is the time to get your results (15-30 minutes), not the waiting time to get tested (up to 6 months).
Saliva Antibody Tests: This test detects antibodies in a substance in the mouth called mucosal transudate, which is very similar to saliva. Because saliva is a low risk body fluid, and because no needles are involved, healthcare workers collecting these specimens are at very low risk of infection. This tests is well suited for persons who do not like getting their blood drawn, or people who have bad veins (who can be difficult to draw blood from). This test is also recommended for testing hemophiliacs, or people on medications that affect bleeding. The saliva test is not currently available for home use. For more information on the saliva test, read the posting The New Saliva HIV Tests.
Urine Antibody Tests: Like the saliva test, the main advantage of the urine test is that needles are not necessary to collect a specimen. Therefore, if a person is a hemophiliac, or if a person has veins that are difficult to collect blood from, the urine test is a good alternative to the blood tests. The urine test is also good alternative for people who do not like getting stuck with a needle, for blood tests. The accuracy of the urine antibody test is similar to that of the blood and saliva antibody tests. The urine antibody test can only be done through your doctor. It is not available for home use.
Urine and saliva both contain extremely low concentrations of HIV, and are therefore low risk body fluids. However, both urine and saliva have antibodies to HIV in them. So although both urine and saliva pose a low risk in terms of the transmission of HIV, we can still use either of these body fluids to see if a person is infected or not, by looking for antibodies in them.
For routine HIV testing in adults, antibody tests are highly reliable, relatively inexpensive, and easy for labs to do. You now have a choice of which antibody test to take, whether it is the antibody tests based on blood, or the saliva antibody test, or the urine antibody test.
Do you want more information on AIDS, STDs or safer sex? Contact the U.S. Centers for Disease Control AIDS hotline, open 24 hours a day, seven days a week, at 1-800-CDC-INFO. Or visit The Body's Safe Sex and Prevention Forum.
Until next time . . . Work hard, play hard, play safe, stay sober!