Evaluation of the sorbents used in the FTA-ABS test.

Treponema pallidum haemagglutination test for syphilis. Evaluation of a modified micro-method.

“…Expensive equipment and skilled staff are necessary for the execution of the TPI and FTA-ABS tests and for the interpretation of results. Criticisms have been made of the immunological specificity of the sorbent used in the FTA-ABS test by several workers (Cannefax, Hanson, and Skaggs, 1968;Rathlev, 1968;Wilkinson and Ferguson, 1968), and of its failure to remove all group reactive antibody from some sera (Kiraly, Jobbagy, and Kovats, 1967;Wilkinson and Wiseman, 1971). False positive FTA-ABS tests have also been reported (Fife, 1964;Buchanan and Haserick, 1970;Kraus, Haserick, and Lantz, 1970).…”

“…Its application to the serological diagnosis of syphilis was first reported by Rathlev (1965Rathlev ( , 1967, using a haemagglutination technique for the detection of specific antitreponemal antibody in which formolized tanned sheep cells sensitized with ultrasonicated material from pathogenic Treponema pallidum (Nichols strain) were used as antigen. This was modified by Tomizawa and Kasamatsu (1966) and Tomizawa, Kasamatsu, and Yamaya (1969), who introduced a different absorbing reagent to remove cross-reacting antibodies.…”

Reactivity in the FTA-ABS test of rabbits hyperimmunized with nonpathogenic treponemes.

“…Several workers have reported that uninoculated Reiter media, several components of the media, and a variety of substances seemingly unrelated to treponemes are effective in removing reactivity of nonsyphilitic human sera (Cannefax, Hanson, and Skaggs, 1968;Rathlev, 1968;Wilkinson and Ferguson, 1968). Although these were preliminary studies representing relatively small numbers of sera, these accounts raise the possibility that perhaps the sorbent activity is not accomplished simply through a binding of natural antibodies by sorbent antigen.…”

Fluorescent treponemal antibody absorption (FTA-ABS) test in yaws.

“…It can easily be argued that the child probably has an early infection and that the two adults were 'old' cases of yaws, in which the immobilizing antibody is absent as it is in a minority of cases of long-standing syphilis (Johnston and Wilkinson, 1968), along with a natural decrease in reagin and group antibody. However, as Rathlev (1968) pointed out, it is extremely unwise to make a diagnosis of treponemal infection on the result of one serological test only, especially the FTA-ABS test, in the absence of clinical signs of infection in the individual. Thus no definite conclusion can be reached on the interpretation of the FTA-ABS test results on these three sera.…”