Reasons For Conducting HIV Antibody Tests

Submitted on March 27, 2012

HIV antibody testing is done to detect the RNA or DNA, or the genetic material of HIV in the blood or other samples. HIV antibodies test can help determine if the patient is HIV positive, and if an infection is present. HIV infects CD4+ called, which are white blood cells and part of the body’s immune system. These help to fight infection. HIV leads to AIDS or acquired immunodeficiency syndrome, which is a long-term chronic disease without any cure.

Once a person gets infected, it might take anywhere between two weeks to six months for the antibodies of HIV to show up in the blood. This period of time is known as the window period or seroconversion period. The person can still spread the disease during this period of time when the antibodies cannot be detected in the blood or in any HIV antibody blood test.

HIV Antibody Tests

    Some of the tests that can be done to check for genetic material or antibodies to the HIV virus include –

  • Enzyme-linked immunosorbent assay or ELISA: This is one of the first tests used to detect the infection. If the antibodies are present or positive then a repeat test is done to confirm the results. If the test results are negative, then the patient need not go in for other tests.
  • Western blot: A more difficult test, the Western blot is done when the results of two ELISA tests are positive.
  • Polymerase Chain Reaction or PCR: This test is done to find if the white blood cells have the HIV DNA or to locate the RNA of the HIV virus.  This test is not done very frequently because it needs expensive equipment and technical skill. PCR is generally done a few weeks after the person has been exposed to the virus. The test can locate genetic material even when the results from other tests have been negative. It can detect a recent infection. It is also used in screening organs or blood before donation.
  • Indirect fluorescent antibody or IFA: This test is done to detect HIV antibodies and confirms the results of an ELISA. This test is not used very frequently as it is very expensive.


These tests are done to detect HIV infection; to screen pregnant women and check if they have the infection or not; check if a newborn baby has got the infection from his mother or not. This test is also done to check if someone has AIDS.