The western blot is a confirmatory test for which antibody?

The western blot test is widely recognized as the confirmatory method for detecting antibodies against the Human Immunodeficiency Virus type 1 (HIV-1). This test is performed following an initial positive screening test for HIV, such as an enzyme-linked immunosorbent assay (ELISA). A western blot utilizes electrophoresis to separate proteins from the virus, followed by transferring them to a membrane where specific antibodies can be detected.

The significance of the western blot lies in its ability to confirm the presence of HIV-1 in a patient's serum, as it identifies specific viral proteins that correspond to immune responses produced by the host. This method is highly specific and provides a reliable means of confirming the diagnosis of HIV infection, which is critical for patient management and treatment decisions.

In contrast, other options, such as CMV antibody detection and HBsAg screening, typically use different testing methodologies that do not involve the western blot as a confirmation step. The diagnosis of serum protein abnormalities also does not correlate directly with the use of western blotting, as this involves a more general analysis of protein levels rather than a specific antibody confirmation. Therefore, the correct association of the western blot with anti-HIV-1 underscores its role in the accurate diagnosis of HIV.