ABSTRACT
The automated haemagglutination assay using Treponema pallidum antigen (AMHA-TP) and the Venereal Disease Research Laboratory (VDRL) test were used to examine 330 163 sera. Reactive results were checked by the fluorescent treponemal antibody-absorption (FTA-ABS) test. When isolated reactivity or non-reactivity in the AMHA-TP test was investigated an estimated margin of error of 0.7% probably wrongly non-reactive and 0.008% presumably false non-reactive results were found. These figures were confirmed by randomised FTA-ABS tests on 504 sera with repeat AMHA-TP tests. The latter is therefore still the most reliable and practicable method for mass screening for syphilis.
Subject(s)
Antibodies, Bacterial/analysis , Syphilis Serodiagnosis , Treponema pallidum/immunology , Hemagglutination Tests , HumansABSTRACT
Routine screening of 404 742 sera by the automated micro-haemagglutination assay (AMHA-TP) and the Venereal Disease Research Laboratory (VDRL) test showed that 9848 specimens gave a reactive result to one of the three assays. Reactive results were confirmed by the fluorescent treponemal antibody absorption (FTA-ABS) test. The possibility of false-positive results varied from 0.04-0.38% of all specimens or from 1.7-15.7% of reactive sera. The VDRL test failed to detect reactivity in 56.54% of sera from patients who had previously been infected with Treponema pallidum. The importance of routine testing by the AMHA-TP is illustrated by the detection of four patients with mesaortitis and two with active neurosyphilis among a selected group of 54 patients who had non-reactive results to the VDRL test. Testing of cerebrospinal fluid specimens by the AMHA-TP test produced more specific results than by the other two tests.
Subject(s)
Syphilis Serodiagnosis/methods , Antibodies, Bacterial , Autoanalysis , Fluorescent Antibody Technique , Hemagglutination Tests , Humans , Syphilis/cerebrospinal fluid , Treponema pallidum/immunologyABSTRACT
Observations made on fluorescent treponemal antibody absorption (FTA-ABS) immunoglobulin M (IgM) titres in patients with untreated early syphilis showed non-reactive or weakly reactive results in patients with primary (one of five cases) and secondary (two of 16 cases) lesions. In patients with primary (19.5%) and secondary (15%) syphilis sera remained reactive with increased titres for more than one year after treatment. The respective figures in the results of the Venereal Disease Research Laboratory (VDRL) test were zero in primary and 20% in secondary syphilis. The non-reactive FTA-ABS IgM results may possibly be explained by competitive inhibition of IgM by immunoglobulin G (IgG). The persistence of reactivity in a comparable percentage has been observed by other investigators (Grin et al., 1974; Wilkinson and Rodin, 1976). The current results therefore suggest that FTA-ABS IgM titres are less reliable for assessing the effect of treatment than the course of the VDRL titres. The phenomenon of a decrease in FTA-ABS IgM titres soon after treatment with a later rise before final non-reactivity is a matter for further investigation.
