The Syphilis TPHA test is a classic, indirect hemagglutination test used for the detection and titration of antibodies against the causative agent of syphilis,Treponema<unk> .
In the test red blood cells (erythrocytes) are sensitized with antigens from T.<unk> . The erythrocytes will then aggregate together to form distinctive patterns on the surface of a microplate wells when exposed to syphilitic serum.
False Positives are common in this test. This is typically caused by antibodies directed against other non-pathogenic or non target treponemas, such as T.<unk>  subsp endemicum,  T.<unk>  subsp pertenue, and T. carateum. These antibodies can be adsorbed out of the test sample by a variety of methods thereby reducing false positives for syphilis.
Treponema pallidum hemagglutination assay 
Heterophile antibody test
Nucleic acid test
Fluorescent treponemal antibody absorbtion 
Mantoux test
Hemagglutination assay
Coronavirus x ray
Viral load