HIV-1 p24 antigen test

Also known as - HIV Screening Tests, AIDS Test, AIDS Screen, HIV Serology, p24 Antigen, HIV test; human immunodeficiency virus antibody test, type 1.

HIV-1 p24 lateral flow one step antigen diagnostic test is intended for research & diagnostics use only.

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Item # Description
IT-200 HIV-1 p24 Antigen test

 

In-depth explanation of our HIV-1 p24 Antigen test

Intended Use:

ImmunoTest™ HIV-1p24 test is an in vitro, semiquantitative immunochromatographic assay for the detection of p24 core protein in blood, serum/plasma, and tissue culture medium samples.

 Principle:

ImmunoTest™ One-Step HIV-1 p24 Test utilizes antibodies specific for the most conserved epitopes of HIV-1 core protein p24 (proprietary) in immunochromatographic assay technology for semiqualitative detection of p24 antigen in, serum, plasma or tissue culture medium. In the test procedure, 20ul of serum/ plasma or tissue culture medium is applied to the sample well (S) of a test cassette. p24 core protein binds to anti-p24 mAb gold conjugate and is then captured by the solid phase p24 specific mAb stripe on the test membrane. Visualization of the p24 core protein in the Test window will occur only when the antibody-dye conjugate binds to the antigen. As the antibody-dye conjugate continues to move along the test membrane, it will bind to another band located in the Control window (C) to generate a colored band regardless of the presence of p24 in the test sample. Therefore, the presence of two colored bands, one in the Test window and the other in the Control window, indicates the presence of p24 core protein in the test sample, while the absence of a distinct colored band in the Test window indicates a negative result. Click here to continue reading.

 

What is this test?

The test looks for HIV-1 antibodies in your blood.

Your body makes these antibodies when you have been exposed to HIV, the virus that causes AIDS.

All tests for HIV antibodies will look for HIV-1, which is more common than HIV-2 in the U.S.  Combination tests have been developed to find HIV antibodies and HIV antigens called p24 antigens. The HIV antibody test recommended by the CDC is the HIV-1/2 antigen/antibody combination immunoassay test.

If you test positive for HIV, the CDC recommends the following follow-up tests:

  • HIV-1/HIV-2 antibody differentiation immunoassay. This test is to confirm HIV and find out whether you have HIV-1 or HIV-2.

  • HIV-1 NAT (nucleic acid test). You will need this test to confirm the HIV-1 infection if you test positive on the first antigen/antibody combination immunoassay test and negative or undetermined on the antibody differentiation immunoassay.

Other follow-up tests, such as ELISA (enzyme-linked immunosorbent assay) and Western blot, may still be used but are not as common as they used to be.

What is being tested?

Human immunodeficiency virus (HIV) is the cause of AIDS (acquired immunodeficiency syndrome). HIV screening tests detect the HIV antigen(p24) and/or HIV antibodies produced in response to an HIV infection in the blood. Some tests detect HIV antibody in oral fluid.

When a person becomes infected with HIV, through exposure to the blood or body fluids of an infected individual or a contaminated needle, for example, the virus begins to replicate itself, producing a large number of copies. During the first few weeks of infection, the amount of virus (viral load) and the p24 antigen level in the blood can be quite high.

About 2-8 weeks after exposure to the virus, the immune system responds by producing antibodies directed against the virus that can be detected in the blood. As the initial infection resolves and the level of HIV antibody increases, both virus and p24 antigen levels decrease in the blood.

An HIV infection may initially cause no symptoms or cause flu-like symptoms that resolve after a week or two. The only way to determine whether a person has been infected is through HIV testing.

If HIV is not detected early and treated, it may become a simmering infection that may cause few symptoms for a decade or more. If the infection is still not treated, eventually symptoms of AIDS emerge and begin to progressively worsen. Over time and without treatment, HIV destroys the immune system and leaves a person's body vulnerable to debilitating infections. (You can read more about this in the article on HIV Infection and AIDS.)

Detecting and diagnosing HIV early in the course of infection is important because:

  • It allows for early treatment that slows progression to AIDS.
  • An individual can learn of their status and modify behavior so as to prevent the spread of disease.
  • A pregnant woman can undergo treatment that would help prevent passing the disease to her child.

There are two types of HIV, 1 and 2. HIV-1 is the most common type found in the United States, while HIV-2 has a higher prevalence in parts of Africa.

A few different testing options are available for HIV screening:

  • Combination HIV antibody and HIV antigen test—the recommended screening test for HIV; it is available only as a blood test.
  • HIV antibody testing—all HIV antibody tests used in the U.S. detect HIV-1 and some tests have been developed that can also detect HIV-2. These tests are available as blood tests or tests of oral fluid.
  • p24 antigen testing—this is used alone without the antibody test only in rare cases when there is a question about interference with an HIV antibody test.

Regardless of the type of screening test used, a positive result requires follow up with supplemental testing to establish a diagnosis of HIV. 

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm or from a fingerstick. There also are tests available that can be performed on oral samples. An oral sample is obtained by using a special small, spatula-like device with a flat pad on the end. The flat pad is placed above the teeth against the outer gum and is swabbed completely once around the outer part of the upper and lower gums.

When To Get Tested?

At least once, when you are 13 to 64 years old; when you think you may have been exposed to the virus; before becoming pregnant or when pregnant; once a year if you are at increased risk of being exposed to the virus



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