Fta test

Detection of Treponema specific antibodies by indirect immunofluorescence, see also Syphilisserology. In the FTA-Abs test (or 19S-IgM-FTA-ABS test) detection of column chromatographically isolated IgM antibodies against Treponema pallidum using fluorescein-labelled anti-human IgM. Reactive from the end of the 2nd week after infection (the test becomes positive in the 1st week of primary action). False-reactive e.g. by IgM class autoantibodies. Highly specific test, see syphilisserology below.

The test antigen (treponema) is fixed on a microscope slide and is fixed with the patient serum and then with the fluorescence-labelled anti-human Ig antiserum and finally evaluated under a fluorescence microscope. Prior to this, potentially cross-reactive antibodies are absorbed by pre-incubation with the so-called "Reiter antigen".