Syphilis is a venereal disease caused by the spirochaete microorganism Treponema pallidum. As this organism cannot be cultured in vitro the diagnosis of syphilis depends on the correlation of clinical data with the specific antibody demonstrated by serological tests.
Serological screening tests for syphilis utilising cardiolipin and lecithin as antigens are simple to perform but biological false positive (BFP) reactions occur frequently because these tests use non-treponemal antigens1. The TPI and FTA-ABS tests utilise pathogenic T. pallidum as the antigen but these tests present some difficulties for routine serodiagnosis. The TPI test requires living pathogenic T. pallidum and the FTA-ABS test requires a fluorescence microscope. Both tests require a high level of expertise.
TPHA assays have been shown to be a convenient and specific test for the diagnosis of treponemal infection, having a specificity similar to that of the TPI test and a sensitivity comparable to that of the FTA-ABS test. It requires minimal laboratory equipment and is very simple to perform. It can be used in conjunction with automated liquid handling systems for improved throughput in the busy laboratory.
Part Number: FTPHA200/1000
Description: Test cells, control cells, Diluent, positive and negative controls
- Convenient and specific test for treponemal infection
- Minimal equipment required
- Simple to perform
- Easily adaptable to automated liquid handling systems for improved throughput
MICROSYPH TPHA200 is a rapid assay for the detection of specific antibodies to Treponema pallidum in human serum or plasma (either di-potassium EDTA, sodium citrate or lithium heparin) by indirect haemagglutination. The kit may also be used for semi-quantitative titration of positive samples.
The 200-test kit contains Control Cells which can be used to assess whether haemagglutination is due to non-specific reactants. This aspect of the kit must not be considered as a confirmatory test for syphilis.
The 1000-test kit is intended to be used as an initial screening test.
MICROSYPH TPHA200/TPHA1000 detects human (serum/plasma) antibodies to T. pallidum by means of an indirect haemagglutination (IHA) method. Preserved avian erythrocytes are coated with antigenic components of pathogenic T. pallidum (Nichol’s strain). These Test Cells agglutinate in the presence of specific antibodies to T. pallidum, and show characteristic patterns in microwell plates.
Antibodies to non-pathogenic treponemes are absorbed by an extract of Reiter’s treponemes included in the cell suspension. Test results are obtained in 60 minutes and the cell agglutination patterns are easily read and stable.
To facilitate the necessary dilution step a blue dye has been added to the Diluent. This changes colour when the sample is added.
In the 200-test kit, any non-specific reactions occurring are detected using the Control Cells which are avian erythrocytes not coated with T. pallidum.
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