Thursday, July 18, 2024

What Is The Name Of Hiv Blood Test

What Happens If My Test Is Positive

The HIV-test – basic information

If you test positive for HIV, it is important to remember that with treatment you can live a long, healthy life. In fact, with early treatment, people with HIV can live about as long as people that are not infected.

A team approach will help you get the medical care and support that you need. Start by talking to your doctor or the counselor or social worker at the testing site. He or she can help you with suggestions on how to talk to your parents or guardians and how to find a health care provider who’s an HIV specialist. By starting treatment as soon as possible, you can stay healthy and learn to live well with HIV.

Screening Donor Blood And Cellular Products

Tests selected to screen donor blood and tissue must provide a high degree of confidence that HIV will be detected if present ” rel=”nofollow”> sensitivity is required). A combination of antibody, antigen and nucleic acid tests are used by blood banks in Western countries. The World Health Organization estimated that, as of 2000, inadequate blood screening had resulted in 1 million new HIV infections worldwide.

In the US, the Food and Drug Administration requires that all donated blood be screened for several infectious diseases, including HIV-1 and HIV-2, using a combination of antibody testing and more expeditious nucleic acid testing . These diagnostic tests are combined with careful donor selection. As of 2001, the risk of transfusion-acquired HIV in the US was approximately one in 2.5 million for each transfusion.

How Is The Test Used

HIV tests are used to screen for and diagnose HIV infections.


Different types of tests may be used for HIV screening:

  • Blood test for HIV antibody and HIV antigen this is the recommended screening test for HIV. The tests that use a blood sample drawn from a vein can detect HIV infections in most people approximately 2 to 6 weeks after infection, while fingerstick blood tests can detect HIV infections 2 to 12 weeks after infection. This combination test increases the likelihood that an infection is detected by testing for both HIV antigen and antibodies:
  • HIV antigen the level of p24 antigen and the amount of virus increase significantly soon after initial infection. Testing for p24 allows for detection of early infections, before HIV antibody is produced.
  • Antibodies to HIV-1 and HIV-2HIV-1 is the most common type found in the United States, while HIV-2 has a higher prevalence in parts of Africa. A few weeks after exposure to the virus, antibodies to HIV are produced in response to the infection and remain detectable in the blood thereafter, making the antibody test useful for detecting infections weeks after exposure.
  • HIV antibody testingall HIV antibody tests used in the U.S. detect HIV-1 and some tests can also detect HIV-2. These tests are available as blood tests or saliva tests. HIV antibody tests can detect infections in most people 3 to 12 weeks after infection.
  • Diagnosis

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    If My Test Is Negative Do I Need Get Tested Again

    Talk to your doctor or the counselor or social worker at the testing site to see if you need to get tested again.

    Some reasons to get tested again include if you:

    • have sex without a condom
    • are a guy who has sex with other guys
    • have had sex with more than three partners in the past year
    • get an STD
    • are a woman and are pregnant

    Accuracy Of Hiv Testing

    Where can I get an HIV test?

    Modern HIV testing is highly accurate. The evidence regarding the risks and benefits of HIV screening was reviewed in July 2005 by the U.S. Preventive Services Task Force. The authors concluded that:

    …the use of repeatedly reactive enzyme immunoassay followed by confirmatory western blot or immunofluorescent assay remains the standard method for diagnosing HIV-1 infection. A large study of HIV testing in 752 U.S. laboratories reported a sensitivity of 99.7% and specificity of 98.5% for enzyme immunoassay, and studies in U.S. blood donors reported specificities of 99.8% and greater than 99.99%. With confirmatory Western blot, the chance of a false-positive identification in a low-prevalence setting is about 1 in 250 000 .

    Many studies have confirmed the accuracy of current methods of HIV testing in the United States, reporting false-positive rates of 0.0004 to 0.0007 and false-negative rates of 0.003 in the general population.

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    Is There Anything Else I Should Know

    HIV infection cannot be cured, but early diagnosis allows for treatment with antiretroviral therapy that can help to suppress levels of virus in the body and greatly improve long-term health. People typically take at least three drugs from two different classes in order to prevent or minimize virus replication and the emergence of drug-resistant strains. Combinations of three or more antiretroviral drugs are referred to as highly active antiretroviral therapy or HAART.

    There is currently no vaccine to protect against HIV, but avoiding high-risk activities such as having unprotected sex and sharing needles for injecting drugs can help to prevent its spread. Early diagnosis of HIV infection is important to prevent its transmission to others and to allow evaluation, monitoring, and early treatment of the affected person.

    While there is no vaccine, the U.S. Centers for Disease Control and Prevention and the World Health Organization recommend that individuals without HIV infection but at high risk for it consider taking pre-exposure prophylaxis , a daily pill to help prevent infection. For people taking PrEP consistently, the risk of HIV infection was up to 92% lower compared to those who didn’t take it.

    Healthcare workers can protect themselves from HIV infection by following universal precautions, such as wearing gloves and avoiding needle sticks.

    Human Immunodeficiency Virus 1 And 2 Preliminary Blood Test

    The HIV-1/2 Preliminary Blood Test includes an Enzyme immunoassay for antigen/antibody screen for HIV-1/O/2 with reflex to supplementary differentiation assay for HIV-1 or HIV-2. Specimens positive by the screening assay but negative by the supplementary antibody typing assay will reflex to qualitative nucleic acid amplification .

    Test Code: 083935

    Also Known As: HIV-1/O/2, 4th Generation Fourth Generation HIV 4th Generation HIV HIV Antigen/Antibody HIV-1 HIV-2 Human Immunodeficiency Virus p24

    Methodology: HIV antigen/antibody enzyme immunoassay screen for antibodies to HIV-1 and HIV-2 and HIV-1 p24 antigen: Reflex to supplementary differentiation assay Screen positive with negative antibody typing: Reflex to qualitative nucleic acid amplification

    Preparation: No fasting required. Stop biotin consumption at least 72 hours prior to the collection.

    Test Results: 1-2 days. May take longer based on weather, holiday or lab delays.

    Test Code: 91431

    Also Known As: HIV-1/O/2, 4th Generation Fourth Generation HIV 4th Generation HIV HIV Antigen/Antibody HIV-1 HIV-2 Human Immunodeficiency Virus p24

    Methodology: Immunoassay

    Preparation: No fasting required. Stop biotin consumption at least 72 hours prior to the collection.

    Test Results: 1-2 days. May take longer based on weather, holiday or lab delays.

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    There Are Several Types Of Hiv Test This Website Can Help You Learn More About Different Types Of Hiv Test Here Are The Basic Types Of Test:

    HIV Antibody Tests Antibody tests do not detect the HIV-virus itself, but detect a protein called an antibody, which is produced by your body in response to the virus. Antibodies are produced by the immune system after it has had time to react to the new infection, which means antibodies are not detectable in the blood or saliva immediately. The window period for antibody-only tests is about 1 month on average, but can take up to 3 months in some people.

    Rapid HIV Tests There are several types of rapid test for HIV, all of which are antibody-only tests. Rapid tests are point-of-care tests . These tests use either saliva or a small amount of blood and provide a result within 30 minutes. Madison Clinic uses a rapid test that takes a few drops of blood and provides a result in less than 60 seconds. The advantage of using a rapid test is that you dont have to wait to get the results however, because a rapid test has a longer window period than other tests and because it is a point-of-care test which is more subject to error in its use than a laboratory test, it is recommended that people getting a rapid HIV test also get a standard laboratory test to confirm the results.

    Why Did Some People Have To Wait For A Year

    types of hiv tests and their accuracy ?

    Good studies usually need to compare two or more groups of people.

    In this case people using PrEP were compared to people not getting PrEP. Everyone in the study was given information and advice on avoiding HIV, including free condoms.

    To make the study more fair, the researchers decided that everyone should have the chance to use PrEP. Half the people in PROUD were due to use PrEP for two years and half for one year.

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    Why Dont People Just Use Condoms

    This is a bigger question than can be answered here but it is commonly asked.

    No-one sets out to become HIV positive and most people are pretty good at using condoms most of the time.

    However, many people find it difficult to use condoms every time, consistently for years.

    Sometimes condoms break or slip off. Sometimes in the heat of the moment you may not have a condom. Sometimes people like sex without a condom because it feels better and they think the risk is low and they will be okay.

    Some people dont use condoms because they think they are HIV negative, when they are really HIV positive.

    Other more complex reasons include the lack of confidence in asking a partner to use a condom, or not understanding the risk for HIV. Some people are in relationships where they want to use a condom but their partner takes no notice.

    Whatever the reasons, HIV figures in the UK shows that other options could have an important role.

    In UK data just released, 6000 people were diagnosed HIV positive last year . More than half were gay men, and of these, 462 were under 24 years old.

    When Can You Get A 4th Generation Hiv Test

    Currently there no HIV tests that can detect the presence of HIV immediately.

    Once someone is exposed to the virus, the body starts producing antibodies, this is called seroconversion. HIV tests cant reliably detect the virus during the window period the time from when a person gets the infection to when tests can detect the virus.

    This time can vary from person to person. Testing too early will give false negative results, meaning you have the virus, but you test negative.

    In some people, the virus can be detected within 2 weeks of exposure, depending on the type of test. The fourth generation test can detect p24 within 1 month of exposure. If you test before the average window period of 18 days, you may get a false negative test.

    If you think youve been exposed to HIV, its important to contact your healthcare provider or visit a health clinic to get tested and begin prevention treatment if needed. If you receive a negative test, be sure to do a follow-up test.

    Your healthcare provider may start you on the pre-exposure prophylaxis medication protocol as a prevention measure. PrEP medications can reduce the risk for infection, if started within 72 hours of high risk exposure.

    The fourth generation test is reliable and highly accurate.

    The reliability of tests depends on:

    • when you get tested
    • which test is used
    • the individual

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    What Do The Test Results Mean

    If a person tests positive for HIV on the ELISA test, they might have HIV. However, there can be false positives with the ELISA test. This means that test results indicate that the person has HIV when they actually do not. For example, having certain conditions such as Lyme disease, syphilis, or lupus may produce a false positive for HIV in an ELISA test.

    For this reason, after a positive ELISA test, more sophisticated tests are done to confirm whether the person has HIV. These tests include the differentiation assay and a test called the nucleic acid test . If the person tests positive for HIV with either one of these tests, they probably have HIV.

    Sometimes, HIV doesnt show up on the ELISA test even though a person has an HIV infection. This can happen if someone is in the early stages of the infection, and their body hasnt produced enough antibodies for the tests to detect. This early stage of HIV infection, in which a person has HIV but tests negative for it, is known as the window period.

    According to the

    What Are The Elisa Test And The Hiv Differentiation Assay

    5 Important Things That Everyone Should Know About HIV Tests

    The enzyme-linked immunosorbent assay , also known as an enzyme immunoassay , detects HIV antibodies and antigens in the blood.

    Antibodies are proteins produced by the immune system, which helps your body fight disease. The immune system produces the antibodies in response to the presence of foreign substances, such as viruses. By contrast, antigens are any foreign substance in the body that causes the immune system to respond.

    The ELISA test is typically the first test ordered by a healthcare provider. In case of a positive result from this test, the ELISA test was previously followed by a test called a Western blot to confirm the diagnosis. However, the Western blot is no longer used, and today the ELISA test is followed by an HIV differentiation assay to confirm HIV infection. The provider may also order an HIV genetic material detection test.

    The ELISA test is recommended if a person has been exposed to HIV or is at risk for contracting HIV. Those at risk for contracting HIV include:

    • people who use intravenous drugs
    • people who have sex without a condom, especially with someone who has HIV or an unknown HIV status
    • people who have had sexually transmitted diseases
    • people who had blood transfusions or blood clotting factor injections before 1985

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    White Blood Cell Count

    White blood cells are immune cells produced in bone marrow whose primary role is to fight infection. There are different types of white blood cells with different roles in immune function.

    A white blood cell count is one of the tests included in the CBC. It measures the total number of leukocytes in a blood sample and also the counts of the different types of white blood cells, namely:

    An elevated WBC typically means that your body is fighting an infection. Other tests can then be performed to pinpoint the cause.

    Increased numbers of certain white blood cells may indicate a specific type of infection or an allergic inflammatory response. For example, higher-than-normal eosinophils may suggest a parasitic infection like toxoplasmosis, while elevated basophils can develop in people with a reaction to a medication.

    A decrease in white blood cells may be the result of HIV medications that suppress the bone marrow, HIV-associated diseases that affect blood cells , or a major opportunistic infection like tuberculosis.

    Lab Tests And Why They Are Important

    Before you start treatment with HIV medicine , your health care provider will order several baseline lab tests. You may start treatment or be referred for treatment before the test results are in.

    Your lab test results, along with your physical exam and other information you provide, will help you and your provider work together to manage your HIV care.

    Your health care provider will repeat some of these lab tests as part of your ongoing HIV care to see how well your HIV medicine is working so that you can get the virus under control, protect your health, and prevent transmitting the virus to others.

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    Can I Just Use Prep When I Need It

    There are different aspects of this question.

    Just taking PrEP when you are going to have sex is unlikely to provide much protection.

    This is because the most active drug in PrEP the tenofovir can take 24 hours to be absorbed into some parts of your body.

    Some ongoing studies are looking at alternative dosing schedules for PrEP. Until other options are proved effective, daily PrEP is recommended.

    However, if your circumstances change so that your risk of HIV changes, you can talk to your doctor about stopping PrEP. If your circumstance change again in the future, you could restart PrEP again. If you do this, remember it takes a week to reach protective drug levels.

    How Long Are The Window Periods Of Different Hiv Tests

    Rapid HIV blood test (HD)

    It is hard to say exactly how long the window period lasts, as there are variations between individuals and it is a difficult topic to research .

    Nonetheless, a study by Dr Kevin Delaney and colleagues calculated window periods for a range of HIV testing assays. All these analyses were based on plasma samples. Window periods are likely to be several days longer when testing samples of fingerprick blood or of oral fluid, as will be normal when using rapid, point-of-care tests and self-testing devices. Unfortunately, precise figures for how much longer the window periods are have not yet been published.

    The researchers analysis confirms that fourth-generation laboratory tests detect HIV infections between one and three weeks earlier than older antibody-only tests. Moreover, their data suggest that some countries guidelines which recommend retesting 90 days after a possible exposure to HIV are more cautious than they need to be.

    Afourth-generation laboratory testis recommended in UK and US guidelines. It uses a sample of blood plasma or serum and can detect immunoglobulin G antibodies, immunoglobulin M antibodies and p24 viral antigen . Commonly used tests of this type include Abbott Architect HIV Ag/Ab, GS Combo Ag/Ab EIA and Siemens Combo HIV Ag-Ab.

    • The median window period is 18 days . This indicates that half of all infections would be detected between 13 and 24 days after exposure.
    • 99% of HIV-infected individuals would be detectable within 44 days of exposure.

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