Which test is primarily used to diagnose HIV?

The HIV antibody test is primarily used to diagnose HIV because it specifically detects antibodies that the immune system produces in response to the HIV virus. This test can identify whether a person has been infected with HIV, typically within a few weeks to a couple of months after exposure.

The process works by examining a blood sample for these antibodies; if they are present, it indicates an HIV infection. This method is widely used because it is accurate and has been utilized for many years in clinical settings, making it a standard diagnostic tool.

While a CD4 count is an important measure for monitoring the health of someone already diagnosed with HIV and assessing their immune system status, it is not used for initial diagnosis. Similarly, a viral load test quantifies the amount of HIV in the blood and is typically used to monitor disease progression and treatment effectiveness, rather than for initial diagnosis. Rapid tests, although useful for on-the-spot screening, are essentially a type of HIV antibody test, but they are not considered the primary test method for formal diagnoses in many healthcare settings. The traditional antibody test remains the cornerstone for diagnosing HIV infection.