HIV 1 and 2 Antibody Screening Test & P24 Antigen Test

What are the HIV 1 and 2 antibody and p24 tests?

HIV or AIDS is an immunodeficiency disorder that weakens our body's immune system. It is spread through direct contact with blood, needle prick injury, or unprotected sex with a person infected by HIV. The human immunodeficiency virus causes HIV, and symptoms usually occur 2 to 4 weeks, but may take even months (what is known as the Window Period), after exposure to the virus. HIV  1 and 2 antibody and the P 24 test helps to detect antibodies for HIV and proteins present on the surface (P24 antigen) of the virus. It is the fourth-generation Test for HIV.

When is the HIV 1 and 2 antibody and p24 Test done?

A doctor may recommend this test in the following.

1. In patients who had come in contact with HIV infected person’s blood/certain body fluids

2. Patients with  high-grade fever (unexplained)

3. As a routine test before surgery

4. In patients who are drug addicts.

5. Giving a history of unsafe sex

6. As a routine investigation of pregnancy/ante natal screening

What are the components of the HIV 1 and 2 antibody and -P24 Test? 

During the first few weeks after an HIV infection, the amount of HIV and the level of p24 antigen in the blood increases. The p24 is produced 2 to 3 weeks after the infection. These are produced before the formation of antibodies. The body begins to produce antibodies after another 2 to 8 weeks; the elevated levels begin to decline after 8 weeks. This Test can detect upto 99% of infections by the end of 6 weeks. P24 is an antigen test. The presence of p24 antigen reduces as the body produces antibodies against it , making p24 more difficult to detect later. P24 antigen test is often used in combination with an antibody test to effectively cover a longer portion of the window period. It is less useful as a standalone test, as it has low sensitivity and only works during the early time period after infection.

 

What is the usual range of the HIV 1 and 2 antibody and p24 Test? 

• A non-reactive result: A non-reactive results mean that the person is not suffering from HIV
• A reactive result: A reactive result means that the person has HIV and needs to take proper medications and medical advice.

Note: A negative test after 4 weeks needs a second test and further investigation. The value may vary from laboratory to laboratory. 

 

How are the HIV 1 and 2 antibody and P24 tests done?

• The blood  sample is collected from the vein 
• The report usually comes within few hours.
• This test does not require fasting.