The fluorescent treponemal antibody absorption test (abbreviated FTA -Abs ) test is a diagnostic detection methods in serology for infection with Treponema pallidum, the causative agent of syphilis (syphilis ). It will be similar to the Treponema pallidum hemagglutination - assay ( TPHA ) antibodies from patient serum demonstrated.
The test is carried out to detect specific antibodies against antigens of pathogenic ( disease-causing ) bacterium Treponema pallidum.
But for example, in the normal flora of the oral cavity may also occur as non-pathogenic Treponema species, against which antigens the body has then formed antibodies ( then incorrectly ) provide also a positive test result, these antibodies have before the actual test is removed from the patient sample - absorbed - are. To this end, the patient's blood serum is first incubated with antigens of a non-pathogenic Treponema species ( sg rider spirochetes ), bind so that existing antibodies to their antigens. Only then the prepared serum sample is applied to a glass slide, on which is fixed antigen structures of Treponema pallidum ( Nichols strain sg, from the brain of a syphilitic asserviert ) are then incubated again. After all unbound material is removed by washing procedures. Now, this slide is coated with specific antibodies labeled with a fluorescent dye and are directed against the already bound ( in the case to be detected ), the human antibody.
Has antibodies against Treponema pallidum antigens in serum, these remain after the washes on the slides stick and can be detected by means of fluorescence-labeled anti-antibody under a fluorescence microscope.
There is both a qualitative and a quantitative FTA -Abs test.
This procedure is necessary to confirm a positive result of the TPHA test.
The phase of the disease (eg, acute or latent) needs with a complement fixation test (CFT ) and possibly a specific IgM -FTA -Abs can be determined.
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