P24 Antigen Test

The HIV P24 antigen is a viral protein which makes up most of the viral core. P24 antigens are produced in response to the HIV infection. This test is used in the detection of P24 antigen from the cultures of a suspected patient. The P24 antigen is produced within 2-3 weeks after the infection and prior to the production of the antibodies. These P24 antigen levels are too high in the first weeks of infection. So this test helps in early detection of the infection. This test is also used for the identification of infection in the newborn babies and also in the early detection of infection in rape cases.

What is HIV?

HIV is the abbreviated form of human immunodeficiency virus. As the name indicates it is a viral infection which leads to acquired immunodeficiency syndrome (AIDS). AIDS can be caused due to either HIV-1 or HIV-2 infection. HIV-1 is the most widely spread virus all over the world. Whereas HIV-2 is prevalent in certain regions like France, West Africa, Portugal, and India. The HIV-2 infection has a slower rate of disease progression when compared to HIV-1 infected individuals. If the individual is infected with HIV, the virus gets replicated by making many copies of itself. The main targeted cells for HIV infection is CD-4. CD-4 cells are a type of white blood cells and help in fighting infections. The virus replicates and spreads all over the body, mostly it gets spread into lymph nodes and spleen. In most cases, the HIV infection remains asymptomatic in early stages of the infection. During this asymptomatic stage, the virus replicates and increases in the number and starts destroying CD-4 cells. For about 3-8 weeks the immune system produces antibodies to fight against HIV and the HIV viral load decreases and the symptoms cannot be seen but the infection remains. Hence it is important to detect the infection as early as possible so that the treatment can be started. This HIV infection can be treated but not cured.

Why this test is performed?

This test may be recommended to you, if you are suspected to have HIV infection (in cases of unprotected sex or shared needles) or previously been diagnosed with an HIV-1 infection or if you are receiving antiretroviral therapy, then to check the effectiveness of the treatment. This test may also be recommended if you experience symptoms like fever, headache, sore throat, dry cough and tiredness for a long time, swollen lymph nodes, muscle aches, joint pains, skin rashes, itching, red breakouts, nausea, vomiting, diarrhea, sweating at night, etc. This test may also be recommended during pregnancy to find out whether you have HIV. And also if you are diagnosed with hepatitis B or hepatitis C or tuberculosis (TB) or any sexually transmitted diseases like gonorrhea, syphilis, chlamydia, etc.,

Precaution:

The HIV P24 antigen test identifies soluble P24 antigen and not specifically the live virus. Therefore a positive test result does not always mean the infection is present. If you get positive test results then this test should be followed with other confirmatory diagnostic tests. In the same way, the negative results do not rule out the infection. If the individual is suspected of the infection but gets a negative result, then he/she should undergo the other screening tests to confirm the condition.

If you get abnormal test results to consult your doctor immediately. Your doctor may recommend other tests depending on your test results.

Frequency:

• This is recommended at least once in when you are 13-64 years.
• Undergo this test once a year if you are at the increased risk of being exposed to the virus. (For e.g having multiple partners, unprotected sex, using needles or sharing needles, diagnosed with STDs, etc)
• This test should be done before planning to get pregnant or when pregnancy is confirmed.

The reference range may vary depending on the gender, age, health history, your condition, etc.

If your test results show positive it means you may have the HIV infection in your body.

If your test results show negative then it means there is no evidence of infection at the time of the test.