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Frequently asked questions
1. What are the different types of HIV Testing Methodologies and what do they mean?
ELISA Methodology
The ELISA (Enzyme Linked Immuno Sorbent Assay), or EIA, is the most commonly used HIV antibody test. It is a highly sensitive test, meaning that all (or nearly all) infected people will test positive.
Western Blot Methodology
The Western Blot test is most commonly used to confirm a positive ELISA test. It is more specific than the ELISA test, so all or nearly all people who are not infected will test negative. The two tests combined result in nearly 100% accuracy.
PCR Methodology
PCR (Polymerase Chain Reaction) detects the virus before the body produces antibodies, and viral culture, where a culture of the virus is produced from a blood sample. Additional tests may be used to assess the functioning of the immune system as a measure of the progression of HIV disease.
NAT Methodology (Nucleic Acid Amplification Testing)
Nucleic Acid Testing, or NAT, is a nucleic acid amplification technology that includes polymer chain reaction, or PCR, to detect certain viral components. NAT enables the earliest and most sensitive detection of disease-causing human viruses in blood and plasma donations.
NAT can detect RNA or DNA from a very small number of virus particles, it can reduce the window period by detecting the infection earlier.
HIV Viral Load
A viral load test is a simple blood test that determines both how active HIV is in the body and how well any antiviral therapy medications are working.
Regardless of what type of specimen is used (blood or oral fluid), ELISA is the first test performed. If the first ELISA test is positive, two additional ELISA tests are performed on the same specimen. If both of these tests are also positive, a Western Blot test is performed. A person is said to have a positive antibody test (to test positive) only when each of these tests is positive. HIV antibody test results may take from two to six weeks to be returned.
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2. What are the different types of HIV?
Human Immunodeficiency Virus (HIV) is the virus that causes AIDS. HIV harms the body's immune system by attacking certain kinds of cells, known as helper T cells or CD4 cells, which defend the body against illness.
Human immunodeficiency virus type 1 (HIV-1) is the etiologic agent of acquired immunodeficiency syndrome (AIDS). AIDS is transmitted by sexual contact, exposure to blood (including sharing contaminated needles and syringes) or certain blood products, or transmitted from an infected mother to her fetus or child during the perinatal period. Additionally, transmission of these viruses can occur through tissue transplantation. HIV-1 has been isolated from patients with AIDS and AIDS-related complex (ARC). HIV-1 was thought to be the sole causative agent of these syndromes until 1986, when a second type of HIV (human immunodeficiency virus type 2 or HIV-2) was isolated and also reported to cause AIDS.
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3. What is AIDS?
AIDS, or Acquired Immunodeficiency Syndrome, occurs when an individual's immune system is weakened by HIV to the point where they develop any number of diseases or cancers. An individual with HIV will also be considered to have progressed to an AIDS diagnosis if their immune system, as measured by their T-cell (or CD4 count) falls below a certain level.
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4. What is the difference between HIV and AIDS?
HIV is the virus that causes AIDS, the most advanced stage of HIV disease. A weakened immune system caused by HIV will allow opportunistic infections (OIs) to develop. A healthy immune system would normally fight off these infections while an HIV-weakened immune system is susceptible.
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5. How Does HIV Testing Work?
In the early stages of HIV infection, the virus itself is difficult to detect. Rather than looking for the virus, HIV testing usually involves looking at the body's reaction to the presence of the virus. The measure of the amount of virus in an individual's blood stream is called the viral load.
Antibodies are produced by the body in reaction to the presence of a virus. In an HIV antibody test, the presence of antibodies in response to the presence of HIV is measured. The most common HIV antibody tests are ELISA (EIA) and Western Blot. These tests can now be performed on samples of oral (mouth) fluid.
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6. What do HIV Test Results Mean?
A Negative Test Result
If an HIV antibody test is negative, no antibodies were detected. A negative test can indicate that a person is not infected with HIV (s/he is HIV negative), or that s/he has been exposed but the immune system has not had time to produce antibodies.
Antibodies to HIV may take up to six months to develop after the initial exposure.
A Positive Test Result
A positive HIV antibody test means that the body has been exposed to HIV (and the body has produced antibodies in response to this exposure). A test result is not reported as positive until it has been confirmed three times, including the use of a different type of test.
When a person has a positive HIV test, it does not mean that the person has AIDS or that the person will have AIDS in a certain amount of time--it only means that the person is infected with HIV.
An Indeterminate Test Result
An HIV antibody test may also be indeterminate or inconclusive. In this case, the presence or absence of HIV antibodies cannot be confirmed. An indeterminate test should be repeated three to six months later with a new blood sample.
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7. How do you get HIV?
In the United States, most people get HIV through unprotected sex, including vaginal, anal and oral sex, and through injection drug use. Certain bodily fluids including blood, pre-cum, semen, and vaginal secretions, spread HIV.
An HIV infected woman can pass HIV to her baby through pregnancy or delivery, and also through breast milk.
According to the U.S. Centers for Disease Control and Prevention contact with saliva, tears, or sweat has never resulted in someone getting HIV. You cannot get HIV through casual contact such as hugging or shaking hands.
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8. How can I tell if I'm infected with HIV?
The only way to determine for sure whether you are infected is to be tested for HIV. You cannot rely on symptoms to know whether or not you are infected. Many people who are HIV positive do not have any symptoms for many years.
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9. How do I prevent getting HIV?
There is no cure or vaccine for HIV, but it is preventable.
- Choosing not to have sex is the only way to be 100% sure that HIV won't be transmitted sexually.
- For those who are sexually active, use a condom for vaginal or anal sex, and barrier methods, such as a condom or dental dam, for oral sex.
- If you are HIV-positive and you are pregnant, see your health care provider to get appropriate treatment. Treatments are available to significantly reduce the risk of passing the infection to your child during pregnancy and delivery.
- Do not share needles for any kind of injection drug use.
- Get tested! And ask your partners to do the same.
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10. Are condoms safe and effective?
Yes. Scientific evidence demonstrates that latex condoms are highly effective in preventing the transmission of HIV when used consistently and correctly. That means you've got to know how to properly use a condom and use one every time.
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11. How do you use a condom?
Just having any old condom around is not going to automatically protect you. Here are some tips to make sure the condom you're using is doing its job:
- Latex or polyurethane condoms are the only ones that protect against HIV infection.
- Check the expiration date on the wrapper; if it's past, throw out the condom. Also look at the condom itself - does it seem dry, brittle, stiff or unusually sticky? Don't take chances, use a different one.
- Store your condoms in a cool, dry place so they don't get damaged. Heat and excessive wear can cause a condom to tear during sex - glove boxes, back pockets, wallets and window shelves are all bad places to keep your condoms.
- To make sure a condom doesn't tear or come off, use some water-based lubricant inside and outside the condom. Be sure not to use an oil-based lubricant like Vaseline or other petroleum jellies, body lotions, mineral or vegetable oils, they can cause the latex to break down.
- Make sure the condom is on correctly before getting started.
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12. What is the connection between HIV and other sexually transmitted diseases?
Having a sexually transmitted disease (STD) can increase a person's risk of becoming infected with HIV. Having STDs that can cause open sores, such as herpes, is especially risky. STDs that do not cause open sores also pose a threat.
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13. Who should be tested for HIV?
HIV/AIDS does not discriminate. The virus does not single out any age, skin color, faith, sexual orientation or economic status. It is not who you are, but what you do that determines whether you can become infected with HIV. You are at risk for being infected with HIV if you have ever:
- had unprotected sex of any kind,
- shared drug needles and syringes,
- had a blood transfusion or clotting factor between 1978 and 1985, or
- had sex with someone whose history of risk-taking behaviors is unknown to you.
If you think you may be at risk, get tested and ask partners to do the same.
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