Rapidindirect enzyme linked immunosorbent assay (ELISA) fordetecting antitoxoplasma IgG: comparison withdyetest

SUMMARY A rapid andsimple enzyme linked immunosorbent assay (ELISA)forthedetectionof specific IgGagainst Toxoplasma gondii was comparedwiththedyeteston 533 serum samples.In general, results werecomparable butnotwith sera thatcontained highconcentrations oftoxoplasma specific IgMorthat hadbeenheated at56°C. There were no false positive results withsera containing rheumatoid factor oranti-nuclear factor. Itisconcluded thatifa dyetestisnottobeperformed thentheserum shouldbe testedforboth toxoplasma specific IgGandIgMtoavoidmisleading results. Heatinactivated serum shouldalsonot betested inthis typeofspecific IgGassay. Various IgGenzymelinked immunosorbent assay (ELISA) methods fordetecting specific antibodies to Toxoplasma gondii havebeendescribed,'2 although themodified dyetest remains thedefinitive test.3 In 1983anIgGELISAinuseattheToxoplasma Reference UnitoftheSwanseaPublic Health Laboratory wasdescribed.4 Thisassayhasbeen simplified andtheincubation conditions changed to produce amorerapid test. We describe animproved ELISAwhichusesa modified cuticular antigen, anditscomparison with thedyetest on533sera. Sera giving anomalous results werefurther investigated. Material andmethods