What Is An Hiv Test
An HIV test shows whether you are infected with HIV . HIV is a virus that attacks and destroys cells in the immune system. These cells protect your body against disease-causing germs, such as bacteria and viruses. If you lose too many immune cells, your body will have trouble fighting off infections and other diseases.
There are three main types of HIV tests:
- Antibody Test. This test looks for HIV antibodies in your blood or saliva. Your immune system makes antibodies when you are exposed to bacteria or viruses, like HIV. An HIV antibody test can determine if you have HIV from 312 weeks after infection. Thats because it can take a few weeks or longer for your immune system to make antibodies to HIV. You may be able to do an HIV antibody test in the privacy of your home. Ask your health care provider about at-home HIV test kits.
- HIV Antibody/Antigen Test. This test looks for HIV antibodies and antigens in the blood. An antigen is a part of a virus that triggers an immune response. If youve been exposed to HIV, antigens will show up in your blood before HIV antibodies are made. This test can usually find HIV within 26 weeks of infection. The HIV antibody/antigen test is one of the most common types of HIV tests.
- HIV Viral Load. This test measures the amount of the HIV virus in the blood. It can find HIV faster than antibody and antibody/antigen tests, but it is very expensive. It is mostly used for monitoring HIV infections.
What Does The Test Measure
HIV tests detect the presence of the HIV virus, HIV antigens, and/or HIV antibodies. If these substances are detected, the test returns a positive result for HIV.
There are three types of HIV tests available:
- Antibody test: Antibodies are produced by the body after an HIV infection. It can take weeks for the body to produce antibodies, so HIV antibody tests can only detect HIV from 3 to 12 weeks after infection.
- Antigen/antibody test: Antigens are foreign substances that activate an immune response. Antigens appear before the body produces antibodies, so HIV antigen/antibody tests can detect an HIV infection earlier than antibody tests, within 2 to 4 weeks of becoming infected.
- HIV viral load test: An HIV viral load test looks for the quantity of HIV virus in the blood. In addition to detecting an HIV infection, viral load testing can also detect how much of the virus is in the blood. Although this type of testing can detect an HIV infection earlier than other HIV tests, its very expensive and is typically only used when someone has symptoms or a possible exposure to HIV.
Discusses Physiology Pathophysiology And General Clinical Aspects As They Relate To A Laboratory Test
AIDS is caused by 2 known types of HIV. HIV type 1 is found in patients with AIDS or AIDS-related complex and in asymptomatic infected individuals at high risk for AIDS. The virus is transmitted by sexual contact, by exposure to infected blood or blood products, or from an infected mother to her fetus or infant. HIV type 2 infection is endemic only in West Africa, and it has been identified in individuals who had sexual relations with individuals from that geographic region. HIV-2 is similar to HIV-1 in viral morphology, overall genomic structure, and its ability to cause AIDS.
Antibodies against HIV-1 and HIV-2 are usually not detectable until 6 to 12 weeks following exposure and are almost always detectable by 12 months. They may fall to undetectable levels in the terminal stage of AIDS when the patients immune system is severely depressed.
Routine serologic screening of patients at risk for HIV-1 or HIV-2 infection usually begins with a HIV-1/-2 antigen and/or antibody screening test, which may be performed by various FDA-approved assay methods, including rapid HIV antibody tests, enzyme immunoassays, and chemiluminescent immunoassays. In testing algorithms that begin with these methods, supplemental or confirmatory testing should be requested only for specimens that are repeatedly reactive by these methods according to assay manufacturers instructions for use.
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What Is It Used For
An HIV screening test is used to find out if you have been infected with HIV. It may be done as a routine test or after a possible exposure to find out if you were infected with HIV.
If HIV is found early, you can take medicines to protect your health so you don’t get AIDS. And medicines can help you avoid spreading HIV to others.
What Do The Results Mean
A negative test result means that no signs of an HIV infection were found in your sample. But that doesn’t always mean that you don’t have HIV. You could have an HIV infection, but it’s too soon for the test to tell and you made need another test later. Your provider or an HIV counselor can explain your test result and let you know if you need another test.
In general, if you have a negative result on a rapid test or an at-home test and a possible HIV exposure that was:
- 90 days ago or longer, you can be confident that you don’t have HIV
- Less than 90 days ago, you will likely need another test later to check for HIV again
A positive test result means that signs of an HIV infection were found in your sample. You will need a follow-up test to confirm an HIV diagnosis unless you had a NAT test.
- If you used an at-home test, see your provider for follow-up testing.
- If you had your test at medical office or community program, the testing site will arrange your follow-up test.
If your follow-up test is also positive, it means you have HIV. It’s important to start medicines called antiretroviral therapy right away, even if you’re still healthy. ART can’t cure HIV, but it may lower the amount of virus in your blood so much that a test can’t find it. If you’re living with HIV, it’s important to see your provider regularly for tests to check how your treatment is working.
Learn more about laboratory tests, reference ranges, and understanding results.
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Clinical Relevance Of Isotype Distribution
Several studies have found correlations with particular HIV-1-specific antibody isotype responses and control of infection or long-term nonprogressor status. The predominant antibody types and specificities that stand out from these analyses are anti-Env IgG2 and anti-Gag antibodies. Despite total IgG2 antibodies being an abundant isotype after IgG1 in serum from uninfected individuals, anti-Env IgG2 antibodies are sporadically detected in chronic HIV-1-positive patient sera at low levels . Due to studies that found a correlation between HIV-1-specific IgG2 antibodies with virus control and T cell help , it is thought that elicitation of a more robust IgG2 response in HIV-1 infection might be of some benefit. However, the function of these IgG2 antibodies is not clear as IgG2 does not bind complement well and only weakly mediates ADCC. Of note, a potentially protective IgG2 subclass response has been demonstrated in age-related anti-measles responses . Studies like the one showing an association between IFN-γ producing HIV-1-specific CD4 Th1 cells and HIV-1-specific IgG2 antibodies suggest that knowledge of the antibody isotypes present may provide some insight into the cellular responses to HIV-1 as well.
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Who Should Get An Hiv Test
The CDC recommends that everyone in the United States between the ages of 13 and 64 get tested for HIV at least once.
You should be tested more often — at least once a year — if youâre at higher risk of getting HIV, including if you:
- Have had several sexual partners since your last HIV test
- Had unprotected sex with someone who is or could be HIV-positive, including someone whose sexual history you don’t know
- Injected drugs using a needle, syringe, or other device that someone else used first
- Have had or are getting tested for tuberculosis, hepatitis, or any sexually transmitted disease, including syphilis, gonorrhea, chlamydia, or herpes
- Are a sex worker
- Had sex with someone who has a history of any of these things
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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. An HIV antibody test measures the presence of antibodies in response to the presence of HIV. The most common HIV antibody tests are ELISA and Western Blot. These tests can now be performed on samples of oral fluid.
The Healthcare Worker There To Help You
Before you test, your healthcare worker will talk to you about your sexual health and why youve decided to test. This is to help them understand your situation so they can offer you the best services and advice.
Remember, the healthcare professional is not there to judge you. There will be nothing you can say that they havent heard before so be honest with them, and ask as many questions as you want. Thats what theyre there for.
You should never feel pressured to test. The results will be completely confidential but you should only go through with it if you want to.
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What Is Rapid Hiv Testing
There are now many tests available which can detect HIV antibodies within a few minutes. Examples of rapid tests include OraQuick, which can detect antibodies in 20 minutes and is the only rapid test that can use oral fluid, and INSTI, which can detect antibodies in under a minute. Other rapid tests are available as well. The technology involved in rapid testing is quite advanced and for any of the various tests, the results are over 99% accurate.
Most community-based organizations who conduct HIV testing in Louisiana follow a rapid-rapid testing model. This means that you will have a rapid test done during your visit and then, if that test is positive, you will have a second test done to verify your result. If both results are positive, you will be offered a referral to medical care. In the very rare event that the second test is negative, your counselor will advise you about next steps.
What Happens When You Go For A Test
Normally, testing involves taking a small sample of blood from your finger or your arm, or an oral swab. This is where you rub the testing pen along your gums to collect cells from your mouth.
How long it takes for HIV test results to come back will depend on the type of test you are taking. If youre taking a rapid test, you will be given your results within 20 minutes. Other types of tests will be sent to a laboratory and it may take between a few days and a few weeks for you to receive a final result.
Tests these days are very reliable, but if your result comes back positive, you should have a second confirmatory test to double check your result. If this is also positive, you will get an HIV diagnosis, after which you can start treatment.
Remember, HIV treatment these days is very effective and people with HIV can live long and healthy lives just like anyone else.
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Testing Positive On Nucleic Acid Tests
In addition to antibody tests, we also have HIV tests that detect viral RNA not necessarily live virus, but parts of the virus genetic material. These are called nucleic acid tests, and they are able to detect very early HIV infections. These tests are not used as often for screening as antibody tests , because results take longer and the test is more expensive. Usually, RNA tests are used to confirm an HIV positive diagnosis after someone tests positive on an antibody test or to see if a person is responding well to treatment.
Some of these viral detection tests are able to detect virus at very low levels. Some research HIV RNA assays can measure HIV RNA levels down to the single copy levels.
We commonly say someone is undetectable if they have a viral load less than 20 copies/mL or 50 copies/mL. Research studies have defined undetectable as any viral load less than 200 copies/mL.
So even if a person has a viral load less than 50 copies/mL or 20 copies/mL, viral RNA will still be detected with one of these viral detection tests.
When To Get Tested
If youâve had a high-risk exposure to HIV very recently, go to the emergency room or call your doctor right away. Examples include unsafe sex with someone who has HIV or if you were sexually assaulted. Emergency drugs called post-exposure prophylaxis may prevent HIV infection. You need to take them within 72 hours after exposure. The sooner you start, the better.
If you don’t get to a doctor in time to get PEP, ask your doctor about getting tested for HIV. For most types of HIV tests, youâll need to wait 2 weeks or more after exposure to get an accurate result. You can infect others soon after you’re exposed, so practice safe sex and take other precautions in the meantime.
Almost everyone who is HIV-positive has detectable levels of antibodies at 3 months. So if you test negative a month or two after your exposure, your doctor may want you to retest after 3 months to be sure.
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What Should I Do If My Test Is Positive
People who have a positive test have the virus in their body and can infect others. Be very careful to keep from spreading the HIV virus. Tell your doctor, dentist, and sex partner so that they can take steps to prevent infection.
- Always use safe sex practices .
- Do not donate blood or organs.
- Do not share needles or other drug-shooting equipment.
- Women should not get pregnant if HIV positive.
What Do The Test Results Mean
It may take up to 2 weeks to get the test results. Results are only given to you. Some states have to report results to the health department. Talk to your caregiver if you have concerns about how the test is reported in your area.
- A positive test means that you may have the HIV virus. It does not necessarily mean you have AIDS. Once a person is infected with this virus, you will remain infected for life. Some people infected with HIV seem healthy and show no symptoms for several years. Others may get sick with AIDS or have symptoms of an HIV infection. You cannot get rid of the virus and it will not go away. There is no cure for HIV infection. There are medicines to help slow down the infection. There are also medicines to help fight other infections that HIV positive people may get.
- A negative test means that you probably do not have the HIV virus. However, you may need to follow up with repeat tests. These tests are especially important if you have done things during the last year that put you at high-risk to get HIV. Your body takes from 6 to 8 weeks to develop the antibodies to HIV.
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Study Design And Participants
BNAb study participants were enrolled in an open-label phase 1b clinical trial at the Rockefeller University and University of Cologne and received three infusions with a combination of two bNAbs, 3BNC117 and 10-1074. ART was interrupted at day 2 after the first antibody infusion . Viral load was assessed every 12 weeks and ART was reinitiated when two consecutive measurements showed viral load of > 200 copies per ml. All individuals were infected with clade B HIV-1 . Clinical data of all participants are shown in Extended Data Figs. and . Individuals on continuous ART were enrolled in an observational study at the Rockefeller University. Clinical data of all ART individuals are shown in Extended Data Fig. . The studies were approved by the Rockefeller University and the University of Cologne Institutional Review Boards and written informed consent was obtained from all participants before study enrollment. Secondary use of samples was approved by the University of Montréal Hospital Institutional Review Board.
Hiv Antibodies And Antigens
When an HIV infection occurs, measurable HIV antibodies are produced in response to antigens within a week or two of exposure. The antibodies are generated in response to different viral antigens.
Once infected, the antibodies persist for life and provide the traditional target for HIV antibody tests .
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Broadly Neutralizing Antibodies As Next
Most antibody carriers explored in the HIV-1 ACs employed murine, polyclonal, non-neutralizing, and/or first-generation neutralizing antibodies. However, the last decade saw increased innovation in the isolation and discovery of bNAbs with increased breadth and potency. BNAbs can be placed in a distinct category than ART because they directly target circulating virus, recognize Env-expressing infected cells, and can directly engage host antiviral responses such as ADCC. Several of these bNAbs have already entered various phases of human clinical trials for prevention, ART interruption, and therapeutic studies . Moreover, bNAbs are an attractive next-generation armed antibody for the delivery of molecular payloads for HIV-1 cure. The fundamental characteristics of bNAbs recognizing conserved epitopes across various clades and strains of HIV-1 remain of utmost importance providing selectivity as well as breadth, but additionally, the whole gamut of isolated bNAbs could offer increased flexibility, adaptability, and customization depending on the payload of choice.