1) Who should be tested?
1. Any sexually active person, regardless of age, should be tested for HIV annually.
2. Any sexually active person who has unsafe sex with multiple partners should have an HIV test at least every three months.
3. Any man or women who participated in commercial sex, either as the client or sex worker.
4. Men who have anal and/or oral sex with other one or multiple men, especially if no condom was used.
5. Persons who have commercially donated blood in China.
6. Persons who received a blood transfusion in any medical setting.
7. Pregnant Mothers as part of prenatal exams.
8. Persons who have shared needles.
9. Persons who have tested positive for active Tuberculosis (TB)
10. Persons who have been diagnosed with STDs
2) What Is HIV Testing?
HIV testing tells you if you are infected with the Human Immunodeficiency Virus (HIV) which causes AIDS. These tests look for "antibodies" to HIV. Antibodies are proteins produced by the immune system to fight a specific germ.
Other "HIV" tests are used when people already know they are infected with HIV. These measure how quickly the virus is multiplying or the health of your immune system.
HIV antibody testing has been since 1985. Testing technology has evolved considerably over the years, with a variety of new and improved tests coming into use, both in research and daily practice. Since determining one's HIV status is the first step in treatment decisions, it is important to understand the tests being used today, including their limitations.
- The Basic Testing Procedure
The primary purpose of the test in 1985 was to screen the blood supply. At the time there were no treatments available for HIV infection and no one knew how likely it was that an HIV-infected person would get AIDS or how quickly it might happen. The only medical interventions available dealt with the opportunistic diseases that appeared once the immune system had weakened, so there was no pressing need for people to find out their HIV status.
Still, it was clear that some who believed themselves at risk would want to know.
Now that antiretroviral therapy and prophylaxis (preventive treatment) aimed at preventing opportunistic infections are available, HIV testing is a gateway to treatment, as well as a prevention tool.
Although there have been technological changes, HIV testing in the China still follows the same basic testing procedure as many developed countries: HIV infection is only considered confirmed after two tests have been done, a screening test and a confirmatory test.
Screening tests possess a high degree of sensitivity, whereas confirmatory assays have a high specificity. Tests with high sensitivity produce few false-negative results, whereas tests with high specificity produce few false-positive results. Because the screening tests can produce false positives, a second screening test is typically run on the same sample -- in duplicate -- with the confirmatory tests only run on samples that are repeatedly positive.
The combination of the two types of tests produces results that are "highly accurate," but technical errors are possible, and biological factors can occasionally produce problems.
The most common screening test is the enzyme-linked immunosorbent assay (ELISA), sometimes called enzyme immunoassay (EIA). The most often used confirmatory test is the Western blot.
The ELISA is used for initial screening because of both its high sensitivity and its practical advantages.
ELISA HIV test kits use artificial HIV proteins that are able to capture antibodies to the virus. Once those antibodies are caught, they can be detected using other reagents that are usually coupled to an indicator such as a dye or enzyme that can produce color. The change in color is read by a machine.
The Western blot is somewhat similar, but uses an electrical field that separates out the various components by their molecular weight. This allows identification of antibodies to specific viral antigens, which show up as identifiable "bands" on a strip of test paper.
The Western blot is a little more complicated to do . It's more hands-on. Because it is less sensitive it should never be run by itself.
Although the Western blot is the most common confirmatory test, others are sometime used, including the indirect fluorescent antibody assay (IFA) and the radioimmunoprecipitation assay (RIPA).
- The "Window" Period Just After Infection
One major drawback of antibody tests is the "window" period: the time it takes the body to produce antibodies after infection has begun. The standard tests for HIV do not detect the virus itself, but the antibodies that the body produces in response. During the period before the antibodies are produced, a person can be infected with HIV and can infect others, but still test negative on the HIV antibody test.
This window period ranged from six to 12 weeks. This is true of just about all of the ELISAs and the rapid tests.
- Oral HIV Testing
All of the early tests were done on blood. More recently developed tests look for antibodies in oral fluid or urine.
The oral test, which follows the same screening/confirmatory protocol as blood tests, has the advantage of being a noninvasive procedure that can be done in settings where blood draws would be impractical or unsafe. It is not a saliva test, but instead uses a small pad to draw fluid from within the gums. These fluids are in fact derived from blood, therefore they include the same fluid (plasma) that is used for testing with serum-based tests.
The pad used to draw the fluid is attached to a small handle resembling a toothbrush. It is placed against the gum, where it must remain for at least two full minutes to collect a proper sample.
Because the saliva present in the mouth dilutes the antibodies obtained, oral tests must be able to detect weaker concentrations of antibodies than blood tests. As a first test, in general oral tests have been found to be accurate. Anyone with a positive oral test should return for a confirmatory test.
- Urine HIV Testing
Urine tests exist as well, but have not been as popular as the oral fluid test. This may be because no confirmatory urine test exists so far, so anyone with a positive urine test must return for a confirmatory test.
- Rapid HIV Testing
Another innovation has been the development of rapid tests. In conventional tests the sample is collected and sent to a central laboratory for processing, a procedure that usually requires the patient to return a week or more later for the results. Rapid tests (which come in both blood and oral versions) are done on-site and give a reading within half an hour. As with the ELISA, a positive reading on a rapid test requires a second, confirmatory assay such as a Western blot.
An advantage of rapid tests is that they eliminate the problem of testers who don't return for their results. Non-return rates are can be fairly high in official test sites and in other settings, including STD clinics, where as many as one third of patients never come back to get their results.
Rapid tests have proved to be as accurate as the ELISA when performed carefully by experienced personnel. Technical errors are common with these assays, however, because users become careless with these simple procedures. To deal with this problem, many rapid tests now include a built-in control that indicates whether or not the test was done properly.
Anyone with a positive rapid test should return for a confirmatory test.
3) How Do I Get Tested?
You can arrange for HIV testing at any local Center for Disease office, most hospitals, and some STD clinics. Test results are usually available within two weeks. For testing locations in your area click here for Testing Locations
The most common HIV test is a blood test. Newer tests can detect HIV antibodies in mouth fluid (not the same as saliva), a scraping from inside the cheek, or urine. Rapid HIV test results are available within 10 to 30 minutes after a sample is taken.. A positive result on any rapid (or regular) HIV test should be confirmed with a second test. The second test could be a rapid test or a regular test.
For testing locations in your area visit The China HIV/AIDS Information Network
4) When Should I Get Tested?
If you become infected with HIV, it usually takes between three weeks and two months for your immune system to produce antibodies to HIV. If you think you were exposed to HIV, you should wait for two months before being tested. You can also test right away and then again after two or three months. During this "window period" an antibody test may give a negative result, but you can transmit the virus to others if you are infected.
About 5% of people take longer than two months to produce antibodies. There is one documented case of a person exposed to HIV and hepatitis C at the same time. Antibodies to HIV were not detected until one year after exposure. Testing at 3 and 6 months after possible exposure will detect almost all HIV infections. However, there are no guarantees as to when an individual will produce enough antibodies to be detected by an HIV test. If you have any unexplained symptoms, talk with your health care provider and consider re-testing for HIV.
5) Do Any Tests Work Sooner After Infection?
Viral load tests detect pieces of HIV genetic material. They show up before the immune system manufactures antibodies. Also, in early 2002, the FDA approved "nucleic acid testing." It is similar to viral load testing. Blood banks use it to screen donated blood.
The viral load or nucleic acid tests are generally not used to see if someone has been infected with HIV because they are much more expensive than an antibody test. They also have a slightly higher error rate.
6) What Does It Mean if I Test Positive?
A positive test result means that you have HIV antibodies, and are infected with HIV. You will get your test result from a counselor who should tell you what to expect, and where to get health services and emotional support.
Testing positive does not mean that you have AIDS. Many people who test positive stay healthy for several years, even if they don't start taking medication right away.
If you test negative and you have not been exposed to HIV for at least three months, you are not infected with HIV. Continue to protect yourself from HIV infection.
7) Can I Keep the Test Result Confidential?
You can be tested confidentially in many places. You may or may not have to give your name when you are tested at a public health office, or when you receive the test results. You can be tested confidentially for HIV as many times as you want.
If you get a positive HIV test that is not anonymous, or if you get any medical services for HIV infection, your name may be reported to the Ministry of Health. Under Chinese law, it is illegal to use your medical data for any reason except providing diagnosis and treatment. It is illegal for local health department to contact your employer or family regarding your HIV status.
The Centers for Disease Control (CDC) proposed that all provinces keep track of the names of HIV-infected people. This proposal has not yet taken effect.
8) How Accurate Are the Tests?
Antibody test results for HIV are accurate more than 99.5% of the time. Before you get the results, the test has usually been done two or more times. The first test is called an "EIA" or "ELISA" test. Before a positive ELISA test result is reported, it is confirmed by another test called a "Western Blot."
Two special cases can give false results:
Children born to HIV-positive mothers may have false positive test results for several months because mothers pass infection-fighting antibodies to their newborn children. Even if the children are not infected, they have HIV antibodies and will test positive. Other tests, such as a viral load test, must be used.
As mentioned above, people who were recently infected may test negative if they get tested too soon after being infected with HIV.
9) The Bottom Line
HIV testing generally looks for HIV antibodies in the blood, saliva or urine. The immune system produces these antibodies to fight HIV. It usually takes two to three months for them to show up. In rare cases, it can take longer than three months. During this "window period" you may not test positive for HIV even if you are infected. Normal HIV tests don't work for newborn children of HIV-infected mothers.
In many places, you can get tested anonymously for HIV. Once you test positive and start to receive health care for HIV infection, your name may be reported to the Department of Health. These records are kept confidential.
A positive test result does not mean that you have AIDS. If you test positive, you should learn more about HIV and decide how to take care of your health.
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For additional information on HIV please visit the following sites:
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