Patient serum is mixed with an absorbent (the "ABS" part of the test) containing an extract of a non-pathogenic treponeme, Treponema phagedenis biotype Rieter.
pˈeɪʃənt sˈɛɹəm ɪz mˈɪkst wɪð ɐn ɐbsˈoːɹbənt ðə "ˈæbz" pˈɑːɹt ʌvðə tˈɛst kəntˈeɪnɪŋ ɐn ˈɛkstɹækt əvə nˈɑːnpˌæθoʊdʒˈɛnɪk tɹˈɛpoʊnˌiːm, tɹˈɛpoʊnmə fˈeɪdʒdɛniz bˌaɪoʊtˈaɪp ɹˈiːɾɚ.