Sunday, April 21, 2024

What Does Hiv 4th Generation Mean

What Is A False Positive Test

Are 4th generation HIV tests 100% accurate if done twice after 3 month? – Dr. Ramakrishna Prasad

You can get a false positive HIV test. This is when a person who doesnt have HIV tests positive.

Newer tests like the fourth generation test are more accurate, but false positive and false negative results can happen for many reasons.

False positive results can happen if:

  • the testing sample is contaminated
  • the lab misreads or mislabels the test
  • youve been part of a HIV vaccine study

Keep in mind, testing blood versus saliva may also affect accuracy of results.

If you receive a positive result, your doctor or clinic where you were tested will recommend a second test to confirm results. This will guide next steps in the process.

There are many options to get tested for HIV with the fourth generation test, including free clinics.

Some options include:

  • sexual health clinic
  • community health center

The Centers for Disease Control and Prevention website has a search tool to locate the nearest testing site by zip code.

Generally, there are no risks to the fourth generation test. Its exactly like any normal blood work or testing done by your healthcare provider during regular checkups.

Occasionally, there may be rare complications:

  • infection from the needle
  • bruising at the blood draw site
  • feeling dizzy or lightheaded

Let your healthcare provider know if youre afraid of needles and if you have any blood disorders that might increase your risk when blood is drawn. If you have any problems after the blood draw, contact the medical office where the test was done.

Visiting A Health Clinic

Most of the sexual health clinics are overloaded with many patients. The wait-times may be quite long to get a test. Personal privacy is not well protected, especially if the clinic specializes in sexually-transmitted diseases. It is somewhat embarrassing for many people to have to sit down in a crowded waiting room with other people, when everyone knows the reason for the visit to the sex clinic and why everyone is there.

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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Specimen Collection And Processing

HIV test types, their testing window and their accuracy ...

A phlebotomy-trained nurse collected approximately 10 ml of whole blood from each participant in 2 separate EDTA tubes , a 9-ml and a 2-ml tube, respectively. The sample in the 2-ml tube was used for HIV rapid testing in the household and for quality assurance testing at the National Reference Laboratory in Mbabane, while the sample in the 9-ml tube was processed into plasma, aliquoted into 1.2-ml aliquots, and stored at â70°C at the NRL for further testing. All specimens were collected, transported in coolers with freezer packs, processed, and stored within 24 h of collection time to ensure specimen integrity for molecular testing. Quality control checks, such as temperature monitoring and time spent in transit, were performed throughout the specimen transportation process to ensure the integrity of the whole-blood samples. Specimens that were unable to meet the 24-h rule were either discarded if the sample was heavily hemolyzed or processed but excluded from NAAT.

Also Check: Is Hiv Testing Included In Std Testing

What Does This Mean For Me

For most people, the best time to test is 3 weeks after having unprotected sex with a new partner. If the test is negative, there is a good chance you do not have HIV from that sexual contact.

If you test at 6 weeks after having unprotected sex with a new partner, and that test is negative, there is a 99% chance you do not have HIV from that sexual exposure.

With any HIV test, you should test again at 3 months to be sure.

Because HIV and other sexually transmitted infection rates are high in gay, bisexual and other men who have sex with men, routine screening every 3 months is recommended.

How Does Treatment Work

Getting and staying on HIV treatment reduces the amount of HIV present in your blood. The goal of ART is to lower the level of HIV in your blood to an undetectable level and keep it undetectable. People who have an undetectable viral load have effectively no risk of spreading HIV to a partner during sex.5 This is commonly known as U=U .

Sticking to your HIV regimen as part of your everyday routine is very important. By taking your HIV medicines consistently every day as prescribed, you can keep your immune system stronger and help prevent drug resistance.

Recommended Reading: What Is Acute Hiv Infection

Lack Of Testing For Hiv Type

Some people may not be aware that there are two types of HIV. The different types of HIV are related, according to i-base, yet they are different diseases. HIV Type-1 is more common and represents up to 95% of all cases. Type-2 only represents about 5% of the cases and is mainly found in a few West African countries.

When being tested for HIV exposure, if the test is only for type-1 HIV, then type-2 will not be detected. The treatment protocols for the two types of HIV are quite different. For extra safety, both types should be tested. The HIV test offered by STDcheck screens for both HIV type-1 and HIV type-2.

Difference Between A 3rd Generation And A 4th Generation Hiv Test

what is a 4th generation hiv test? – accuracy, window period.

The main difference, reported by i-base, between 4th generation HIV testing and the 3rd generation capabilities is that 4th generation HIV tests are able to detect p24 antigens. The identification of p24 antigens in the blood indicates the actual presence of certain HIV virus proteins. This is direct evidence that the blood contains the HIV virus.

Virginias Department of Health notes that the appearance of p24 antigens in the blood, after HIV exposure, happens faster, when compared to the bodys immune response of making HIV antibodies. HIV antibodies show up only after the body recognizes the exposure to HIV. The 3rd generation HIV testing only detects HIV antibodies and does not check for the presence of any p24 antigens.

Also Check: How Hiv Is Transmitted During Intercourse

Appendix : Different Types Of Hiv Test

Different HIV tests work by looking for three different things.

  • Proteins on the surface of the virus like protein 24 .
  • An immune response to the virus .
  • Genetic material from the virus .
  • In this section we describe the main HIV tests.

    • Antigen only . These are rarely used.
    • Antibody only tests . These are rarely used because of more recent availablilty of joint Ag/Ab tests.
    • Combined antibody-antigen tests. These are the most commonly recommended tests in the UK. these test for p24 plus antibodies.
    • Viral load tests

    More details about how the tests work and the science behind them is included in Appendix 3.

    Hiv 1 Screen 4th Generation Wrfx Non Reactive

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    Read Also: When Did Hiv Start In The Us

    How Do Hiv Tests Work And What’s Involved


    • There are plenty of places which offer free HIV testing you can find your nearest provider either by searching online or asking a healthcare professional.
    • Testing for HIV is a simple and pain-free process. It involves giving a small sample of blood or oral fluid.
    • Your results will be confidential and the healthcare provider will be able to explain the process and answer any questions you have. They are there to help you.
    • HIV tests are very reliable. Some HIV tests will give a result within 20 minutes and others are sent to a lab so it may take a few weeks to get your results.

    It is really common to feel a little worried about going for an HIV test, but making the decision to test is the best thing you can do for your health. The process is quick, painless, confidential and almost always free.

    Give Samples For Testing

    4th generation HIV Test Kit  AW Guide

    After choosing the desired tests online and paying the lab fee, a person goes to the nearest clinic facility to give samples for testing. There are over 4,500 clinics in the USA. The process does not require an appointment and usually takes only about five minutes.

    The person uses an anonymous identification number and a Lab Requisition Form that they are given when paying for the test online at They give this form and number to get their blood drawn at the lab. Testing for some other STDs may require also giving a urine sample.

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    Question 4 How Long After Exposure Can Fourth

    A study using a variety of HIV-1 seroconversion sample panels, in conjunction with statistical modeling, estimated that half of patients become repeatedly reactive on fourth-generation testing within 18 days after HIV infection more than 99% have reactive results within 45 days after HIV acquisition. Therefore, HIV infection is very unlikely in patients with negative fourth-generation test results at least 45 days after the most recent exposure.11

    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, AIDS-related complex, and 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 patient’s 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.

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    Hiv 1/2 Antigen/antibody Blood Test

    The HIV Antigen/Antibodies Test also known as the HIV 4th Generation Test, is the most common option for routine HIV Screening. This test typically sees results in just 1-2 business days and is one of the most affordable HIV tests available. The 4th gen test can be used to screen for both HIV-1 and HIV-2. HIV-1 is by far the most common form of HIV in the United States and the world. HIV-2 is mainly present in Western Africa but has appeared in other parts of the world as well. The 4th generation test looks for both antibodies to the HIV virus and the p24 Antigen which is specific to HIV. Antibodies to HIV typically begin to develop several weeks after exposure. In the majority of people, these antibodies will be detectable by 12 weeks from the point of exposure. In some people, antibodies may be detectable as early as 4 weeks from exposure. The p24 Antigen is a viral protein that makes up the majority of the HIV viral core . P24 Antigen levels are typically highest a few weeks after exposure and drop to undetectable levels during the time when antibodies begin to develop. The combination of screening for both antibodies and antigen allow this test to detect a significantly higher number of early infections than previous generations of HIV screening.

    Turnaround for this test is typically 1-2 business days but will be longer if additional testing is necessary.

    What is HIV?

    What are the Symptoms of HIV?

    How is HIV treated?

    Who should get an HIV test?

    Detection Period:

    Question 12 What Percentage Of Patient Specimens Tested With The Fourth

    Negative results of 4th generation HIV & ELISA tests after few months – Dr. Ramakrishna Prasad

    A retrospective unpublished evaluation of approximately 23,000 samples tested at Quest Diagnostics using the fourth-generation HIV screening algorithm found that only 0.16% required reflex testing through the final step in the CDC HIV diagnostic algorithm .


  • Panel on Antiretroviral Therapy and Medical Management of HIV-Infected ChildrenA Working Group of the Office of AIDS Research Advisory Council . Guidelines for the use of antiretroviral agents in pediatric HIV infection . .Accessed July 28, 2014.
  • Branson BM, Handsfield HH, Lampe MA, et al. Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings. MMWR Recomm Rep. 2006 55:1-17. .
  • Screening for HIV: U.S. Preventive Services Task Force recommendation statement. Published April 2013. July 28, 2014.
  • Stekler JD, Branson BM. Detection of acute HIV infection: we cant close the window. J Infect Dis. 2012 205:521-524.
  • Branson BM, Owen SM, Wesolowski LG, et al for Centers for Disease Control and Prevention and Association of Public Health Laboratories. Laboratory Testing for the Diagnosis of HIV Infection: Updated Recommendations. . Published June 27, 2014. Accessed June 27, 2014.
  • Document FAQS.106 Version: 3

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    Question 10 Is Pregnancy Associated With A Higher Frequency Of Biological False

    There have been anecdotal reports of pregnancy being associated with a higher frequency of biological false-positive HIV screening test results. This anecdotal association may have been due to an initially greater frequency of testing of pregnant women prior to issuance of the 2006 CDC HIV testing recommendations. A more recent large epidemiologic study using a third-generation HIV screening method did not demonstrate a greater propensity toward biological false positivity in pregnant subjects. In this study of more than 2 million third-generation HIV antibody screening tests, the false-positive rate was actually lower for pregnant women than for others .8

    Is This A Legitimate Test

    Yes. Our 4th generation HIV tests are CE marked, FDA approved and WHO approved.

    Page reviewed by Dr. Manoj Malu

    Last reviewed date: 18 March 2021Next review due: 18 March 2024

    Whilst this content is written and reviewed by sexual health specialists, it is for general guidance only. It is not intended to replace the advice of your clinician.

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    Which Test Can Give Me Results The Soonest

    The period of time also differs, depending on which kind of test you take. The different types of tests include:

    • Antibody tests, which look for the antibodies — special proteins that help fight infection — that your body makes in reaction to an HIV infection. Most rapid tests and at-home tests are these kind. Antibody tests require the longest wait time after infection to get an accurate result. For most people — around 97% — this takes anywhere from 2 to 12 weeks. For some, it can take as long as 6 months.
    • Combination or fourth-generation tests, which look for both antibodies and antigens. Antigens are part of the virus itself. One antigen, p24, is detectable before your body starts making antibodies. These tests are becoming more common in the U.S. They can tell you if you have HIV a little sooner than an antibody test can.
    • Nucleic acid tests , which can detect HIV in your body the soonest after infection. The test looks for the virus in your blood. You need a certain amount of the virus in your blood before the test will detect it. This is called your viral load. You can get a negative test if your viral load is still low. A NAT can tell you if you have HIV as early as 7 to 28 days after infection. It gives the quickest result, but itâs also the most expensive. Doctors donât typically use it unless youâre at a high risk of exposure to HIV.

    Youâre more likely to have a NAT if you:

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