What does the agglutination of RBCs in the MHA-TP test indicate?

The agglutination of red blood cells (RBCs) in the MHA-TP (Microhemagglutination Assay for Treponema pallidum) test indicates the presence of antibodies specific to Treponema pallidum. This bacterium is the causative agent of syphilis, and the MHA-TP test is a serological assay used to detect these specific antibodies in a patient's serum.

When the patient has been infected with Treponema pallidum, the immune response generates antibodies that specifically target components related to the pathogen. During the MHA-TP test, these antibodies will interact with antigens from the bacteria, leading to the agglutination response when mixed with RBCs coated with these antigens. Therefore, a positive agglutination result directly correlates with active or past infection, confirming the presence of Treponema pallidum antibodies in the patient’s serum.

Other options are misleading in association with the agglutination phenomenon seen in this test. For instance, while the presence of non-specific antibodies may lead to agglutination in other contexts, it does not apply in this specific serological test focused on Treponema pallidum. Similarly, complement