01846nas a2200301   4500000000100000008004100001260001300042653002600055653002900081653003500110653002700145653001100172653001700183653002100200653001200221653001300233653002700246653002300273100001500296700001800311700002000329700001400349245010400363300001100467490000700478520104500485022001401530       1973                            d  c1973 Apr10aAntibodies, Bacterial10aFalse Positive Reactions10aFluorescent Antibody Technique10aHemagglutination Tests10aHumans10aImmunization10aImmunoglobulin E10aleprosy10aSyphilis10aSyphilis Serodiagnosis10aTreponema pallidum1 aGarner M F1 aBackhouse J L1 aDaskalopoulos G1 aWalsh J L00aThe Treponema pallidum haemagglutination (TPHA) test in biological false positive and leprosy sera.  a258-600 v263 a<p>The Treponema pallidum haemagglutination (TPHA) test was carried out on 274 sera known to show biological false positive reactions to reagin tests for syphilis. The Treponema pallidum immunization (TPI) and fluorescent treponemal antibody absorption (FTA-ABS) tests were non-reactive on all these sera. Thirty-one or 11.3% showed reactive results in the TPHA test. Sera from 267 people who had lepromatous leprosy were also tested in the TPHA test. Fourteen sera were reactive in the TPHA, TPI, and FTA-ABS tests and were from people who had both syphilis and leprosy. Biological false positive reactions were shown by 26 of the leprosy sera, of which three or 11.5% were also reactive in the TPHA test. A further four sera in the leprosy group were reactive only in the TPHA test. The possible cause of false reactive TPHA test results is discussed. It was concluded that where reagin and TPHA tests are reactive in a person who has no history or clinical signs of syphilis, the serum should be referred for TPI and FTA-ABS testing.</p>  a0021-9746