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What Is Hiv 1 And 2

What Are The Types Of Hiv Tests

Alere Determine HIV-1/2 Ag/Ab Combo – Venipuncture Procedure Demo

There are three types of human immunodeficiency virus tests used to diagnose HIV infections, which are

  • Antibody tests: These tests check for HIV antibodies in the blood or oral fluid.
  • Antigen/antibody tests: These help to detect both HIV antibodies and antigens in the blood.
  • Nucleic acid tests: These look for HIV in the blood.

Can I Take The Test At Home

At-home HIV tests are a convenient way to take an HIV test in a private location. Testing for HIV at home is a form of HIV screening that requires additional follow-up if preliminary results are positive. At-home HIV tests can be obtained online, at a pharmacy, or at health departments and community-based organizations.

What Happens During An Hiv Test

You will either get a blood test in a lab, or do your own test at home.

For a blood test in a lab:

  • A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

For at home test, you will need to get a sample of saliva from your mouth or a drop of blood from your fingertip.

  • The test kit will provide instructions on how to get your sample, package it, and send it to a lab.
  • For a saliva test, you will use special spatula-like tool to take a swab from your mouth.
  • For a fingertip antibody blood test, you will use a special tool to prick your finger and collect a sample of blood.

For more information on at-home testing, talk to your health care provider.

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What Is A False Positive Test

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.

What Are The Four Stages Of Hiv


The World Health Organization classifies human immunodeficiency virus into four stages

  • Stage 1 : The CD4+ cell count is at least 500 cells per microliter.
  • Stage 2 : The CD4+ cell count is 350 to 499.
  • Stage 3 : The CD4+ cell count is 200 to 349.
  • Stage 4 : The CD4+ cell count is less than 200.

The normal CD4+ cell count should be between 500 and 1600 cells per microliter. The higher the CD4+ cell count, the lower the chances of opportunistic diseases.

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Infections With Multiple Strains

When the virus multiplies, the copies sometimes change and develop into another HIV strain in your body. You can end up with a strain your HIV drugs won’t work against. This makes your viral load — the amount of HIV in your body — go up. In that case, you’d need another type of treatment.

You also can have two or more strains if you were infected by more than one person. This is called superinfection. Superinfection is rare — it happens in less than 4% of people. You’re at the highest risk of superinfection in the first 3 years after you get HIV.

Everyone reacts differently to infection. You might not notice any change in your symptoms or viral load with a new infection. But it can make your HIV worse, especially if you have a strain drugs won’t work well against. If that happens, the drugs you take for your original HIV strain won’t necessarily treat the new strain.

AIDSinfo: “HIV-1.”

AVERT: “HIV Strains and Types.”

CDC: “Morbidity and Mortality Report: HIV-2 Infection Surveillance — United States, 1987–2009,” “Infection with more than one HIV type .”

HIV Sequence Database: “HIV and SIV Nomenclature.”

Minnesota Department of Health: “HIV Drug Resistance and Subtype Testing: Information for Clients.”

Motomura, K. Journal of Virology, 2008.

Nyamweya, S. Reviews in Medical Virology, 2013.

Plantier, J. Nature Medicine, 2009.

Public Library of Science: “The Two-Phase Emergence of Non-Pandemic HIV-1 Group O in Cameroon.”

Do Differences In Subtypes Matter

Some studies suggest that certain subtypes have a greater risk of transmission or faster disease progression than others but more recent research suggests that this may not be the case.9 On the other hand, antiretroviral drugs , although largely tested in people with subtype B, have generally proven to be effective against a wide range of subtypes (although there is conflicting evidence about the effectiveness of protease inhibitors against subtype C virus.10111213

A more practical concern are the tests used to diagnose HIV and monitor the level of virus in the body . Tests that are sensitive to the full range of subtypes do exist but may not be readily available in all settings. This is a concern in places where diverse subtypes are prevalent.

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The Accuracy Of Different Hiv Antibody Tests

A wide range of point of care tests have been made in many countries, but few of them have undergone rigorous and independent assessments. Research on HIV screening tests is only occasionally published in medical journals. Lab professionals may have insight into which tests work best. Extensive research studies have shown that the INSTI HIV-1/HIV-2 Antibody Test is extremely accurate when performed correctly. The accuracy of medical tests is typically described in terms of sensitivity and specificity. Sensitivity means that all HIV-positive individuals test positive. Specificity means that all HIV-negative persons test negative. In US clinical studies, our fast HIV test shows to have a sensitivity of over 99.8% and a specificity of over 99.5%.

What Is The Difference Between Hiv

INSTI HIV-1 / HIV-2 Antibody Test: Controls Test Procedure

There are two main types of the human immunodeficiency virus , HIV-1 and HIV-2. The difference between HIV-1 and HIV-2 are as follows

  • HIV-1 is the most common type of HIV and accounts for 95% of all infections, whereas HIV-2 is relatively uncommon and less infectious.
  • HIV-2 is mainly concentrated in West Africa and the surrounding countries.
  • HIV-2 is less fatal and progresses more slowly than HIV-1.

Currently, only one antibody test can distinguish between antibodies to HIV-1 or HIV-2.

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How Much Does The Test Cost

The cost of an HIV test is usually covered by insurance without a copay, although specific costs depend on a persons insurance coverage and where the test is performed. Check with your health plan and health care provider for specific cost details.

At-home HIV tests cost below $50. Health departments and community-based organizations may provide HIV self-test kits for free or at a reduced cost.

How Do I Know If I Have Hiv

The only way to know for sure if you have HIV is to get tested. Testing is relatively simple. You can ask your health care provider for an HIV test. Many medical clinics, substance abuse programs, community health centers, and hospitals offer them too. You can also buy a home testing kit at a pharmacy or online.

To find an HIV testing location near you, use the HIV Services Locator.

HIV self-testing is also an option. Self-testing allows people to take an HIV test and find out their result in their own home or other private location. You can buy a self-test kit at a pharmacy or online. Some health departments or community-based organizations also provide self-test kits for free.

Read the U.S. Food and Drug Administrations fact sheet on the OraQuick In-Home HIV Test, the only FDA-approved in-home HIV test.

The coronavirus pandemic has made it more difficult for some people to access traditional places where HIV testing is provided. Self-testing allows people to get tested for HIV while still following stay-at-home orders and social distancing practices. Ask your local health department or HIV service organization if they offer self-testing kits.


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Pathogenesis Of Hiv Infection

HIV infects certain types of white blood cell specifically helper T-lymphocytes, monocytes and some other cells that are key elements of the human immune system. This usually results in the death of these cells. The hallmark of HIV infection is the gradual loss of helper T-lymphocytes from an infected person. This ultimately leads to a state of generalised immunodeficiency and AIDS. In some cases, infection of the central nervous system occurs, often leading to progressive brain damage .

Several different conditions may occur as a result of HIV infection that precedes the development of AIDS. Most infected individuals generate antibodies to HIV within a few weeks after infection and, during this period, may develop a self-limiting illness resembling glandular fever . After a longer period, some develop a long-lasting generalised enlargement of the lymph glands. Other non-specific symptoms are associated with progressive immune dysfunction. When AIDS develops fully, which often takes several years, it is characterised by the appearance of secondary opportunistic infections and tumours.

What Are The Symptoms Of Hiv


Not everyone will have identical symptoms because it depends on the person and what stage of the disease they are in.

There are three stages of human immunodeficiency virus . Each stage has a unique set of symptoms. These include the following

Stage 1: Acute HIV infection

This stage starts around two to four weeks after getting HIV. The symptoms are similar to those of the flu, which last for a week or two. Symptoms include the following

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Hiv Testing After Diagnosis

Additional tests are performed both after a person receives an HIV-1 diagnosis and throughout their treatment. These include:

  • Viral load. The amount of virus in a persons blood is called viral load. When HIV-1 isnt treated, viral load will increase. In contrast, treatment with antiretroviral drugs can reduce viral load to undetectable levels.
  • CD4 count. A CD4 count looks at the number of CD4 cells in a blood sample. Decreasing levels of CD4 cells signal damage to the immune system.
  • Drug resistance testing. HIV-1 can become resistant to certain types of antiretroviral drugs. Because of this, drug resistance testing is performed to help inform which antiretroviral drugs can be used for treatment.

HIV is a viral infection. A person can contract HIV-1 when bodily fluids that contain the virus come into contact with their blood or with mucous membranes like those found in the genitals, anus, or mouth.

There are several bodily fluids that can transmit HIV-1. These include:

  • blood
  • workplace exposures, such as accidental needlesticks or sharps injuries
  • receiving a blood transfusion or organ transplant
  • getting a tattoo or piercing with equipment that hasnt been properly sterilized
  • human bites that break the skin

What Is The 4th Generation Hiv Test

The fourth generation HIV test, also called an enzyme-linked immunosorbent assay test, is a more complete screening that can identify acute HIV. This is the time when the virus is multiplying rapidly and youre more likely to pass the infection.

In the first few weeks after exposure to HIV, your body produces an antigen known as p24. This protein is only present in people who have acute HIV infection. It triggers your immune system to respond.

The fourth generation tests can identify both HIV-specific antigen p24 and HIV antibodies with a blood sample.

The fourth generation tests require a blood sample thats sent to a lab for testing. Blood testing done by a lab is the most accurate type of test.

There are many products approved for fourth generation testing, including:

  • ADVIA Centaur HIV Ag/Ab Combo Assay
  • Elecsys HIV Combi PT
  • Genscreen ULTRA HIV Ag-Ab
  • VITROS HIV Combo Test

The healthcare clinic or doctors office you visit for an HIV test can tell you more about the exact test they use.

tests that can test for the presence of HIV. HIV testing can be done by drawing blood from a vein, a finger stick, or taking an oral swab of fluid.

Tests can measure antibodies, antigen/antibody , and theres also a nucleic acid test . The NAT test can identify HIV and viral load . It can tell if you have HIV within around 10 to 33 days of exposure.

Older tests like the third generation tests arent reliable until about 3 months after exposure to the virus.

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Can You Prevent Hiv

There are many steps that a person can take to prevent contracting HIV-1. These include:

  • Using a condom. Using a condom during vaginal, anal, or oral sex can help prevent transmission of the virus during these activities.
  • Getting tested. Getting tested for HIV and other sexually transmitted infections is a powerful tool for both detecting and treating these infections. Encourage sexual partners to get tested as well.
  • Not sharing needles. Its important that injection drug users avoid sharing needles or injection drug equipment with others.
  • Taking pre-exposure prophylaxis .PrEP is a daily medication that can be taken to help greatly lower the risk of contracting HIV through sex or by using injection drugs.
  • Using post-exposure prophylaxis .PEP is a medication that can be used in emergencies to prevent contracting HIV. To be effective, it needs to be started within 72 hours of possible exposure.

Clinical Course Of Hiv

INSTI HIV-1 / HIV-2 Antibody Test: Controls Test Procedure (Canada)

The clinical course of HIV-2 infection is generally characterized by a longer asymptomatic stage, lower plasma viral loads, and a lower mortality rate than HIV-1 infection.2,3 However, without effective antiretroviral therapy , HIV-2 infection will progress to AIDS and death in the majority of individuals.4 Concomitant HIV-1 and HIV-2 infection may occur, and the possibility of this coinfection should be considered when treating persons from areas with a high prevalence of HIV-2.

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What About Reports Of Cured People

Only two people, Timothy Brown and Adam Castillejo, have been completely cured of HIV.

During treatment for acute myeloid leukemia, Brown received a bone marrow transplant from a donor who had a genetic mutation that leads to HIV resistance.

After the transplant, doctors could no longer detect HIV in Browns body. The exact reason why is still unknown.

Castillejo also received a bone marrow transplant, but to treat lymphoma. Like in Browns case, the donor had a genetic mutation that leads to HIV resistance.

Reports of other cured people may actually refer to long-term nonprogressors . While progression to AIDS is still possible without antiretroviral drugs, LTNPs are able to maintain stable viral loads and CD4 cell counts for long periods of time.

About 5 to 15 percent of people living with HIV are LTNPs. LTNPs can also be broken down further based off their viral load:

  • Viremic controllers are people who maintain a viral load at very low, but still detectable, levels.
  • Elite controllers are people who maintain viral load at undetectable levels. Elite controllers are very rare. Its estimated that they make up less than 1 percent of people living with HIV.

There have also been reports of HIV-1 control in people who have previously taken antiretroviral drugs. These people are called post-treatment controllers and are also rare.

How Does The 4th Generation Hiv Test Work

The fourth generation test is different because its a combination test thats more advanced. It can detect both HIV antibodies and the p24 antigen, which is associated with HIV. Testing for p24 allows earlier detection and diagnosing of acute HIV infection.

For a fourth generation test, youll have a small sample of blood drawn from a vein with a needle. You might feel a small sting from the needle. It takes a few minutes to take the sample. Once the sample is collected, itll be tested in a lab.

Results are available in a few days or in some cases, a few weeks.

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Clinical Trials For The Treatment Of Hiv

There are limited data from clinical trials that inform guidance on the optimal timing or regimen for initial antiretroviral therapy of persons with HIV-2, though several clinical trials are in progress, including a trial comparing tenofovir DF-emtricitabine plus raltegravir versus tenofovir DF-emtricitabine plus lopinavir-ritonavir. The lack of data on HIV-2 treatment is due to a combination of factors, including the low prevalence of HIV-2 and the lower virulence of HIV-2 compared with HIV-1, which has made investigation of antiretroviral therapy for HIV-2 less of a priority than for those with HIV-1.

Difference Between Hiv 1 And Hiv 2


Categorized under Disease | Difference Between HIV 1 and HIV 2

HIV 1 vs HIV 2

AIDS is one of the most feared diseases in the world and currently has no known cure. This disease is caused by the Human Immunodeficiency Virus, commonly known as the HIV. What most people do not know is that there are two strains to HIV and they are simply known as HIV 1 and HIV 2. The main difference between the two is the frequency of occurrence. HIV 2 is much rarer than the common HIV 1. Its occurrences are also limited to Africa unlike HIV 1, which is widespread across the globe.

Although both diseases exhibit the same symptoms and eventually lead to AIDS, they do have differences in how they progress. In the early stages of the disease, HIV 1 is more infectious and is probably the reason why it spreads much faster than HIV 2. In later stages, HIV 2 becomes more infectious than HIV 1 but it is more likely that the disease has already been discovered and precautions have already been taken to not infect other people.

HIV 2 is harder to detect mainly because of the fact that the most prevalent tests are only sensitive to the HIV 1 infection and not HIV 2. More recent tests are now sensitive to both strains but it is advised for people who think that they may have HIV 2 to seek out tests specific to HIV 2 if the test for HIV 1 turns out negative just to be sure.


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