HIV Antibody Screening and Confirmation (gp120 Antigen)

Why This Test Is Done

Your healthcare provider may recommend this HIV antibody test if you have symptoms of infection, such as fever, fatigue, or unexplained weight loss. It’s also used as part of routine screening for high-risk groups, like those with multiple sexual partners, intravenous drug use, or exposure to HIV through blood transfusions or sharing needles. Some people are tested as part of pre-exposure prophylaxis (PrEP) or post-exposure prophylaxis (PEP) regimens. Additionally, it may be used in routine health check-ups for individuals at higher risk.

How the Test Works

The test uses a blood sample (usually serum or plasma) to detect antibodies against the HIV-1 gp120 protein. Antibodies are proteins your immune system produces in response to infection. If you have been exposed to HIV, your body will produce these antibodies over time. The test looks for these antibodies to determine if HIV is present in your system.

Sample Collection and Preparation

A small amount of blood is drawn from a vein, typically in your arm, using a needle. The blood is then processed to separate the serum or plasma, which is sent to a lab for testing. This process is quick and usually done in a healthcare provider’s office or clinic.

Test Results and Interpretation

Results are typically reported as either positive or negative. A positive result means your blood contains antibodies or antigen to HIV, indicating possible infection. A negative result means no detectable antibodies or antigen were found at the time of testing. Follow-up testing may be recommended if results are unclear or if you have symptoms of HIV.