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VDRL Carbon Antigen / RPR
Syphilis is a veneral disease caused by the
spirochaete micro-organism T.pallidum. As the organism cannot
be cultured on artificial media the diagnosis of syphilis depends on
the correlation of clinical data with the detection of specific
antibody by serological tests. Serological screening tests for
syphilis using cardiolipin and lecithin as antigens are simple to
perform but may give rise to a small proportion of false positive
results because the tests use non-treponemal antigens. The test
antigen is a modified form of VDRL Antigen containing
microparticulate carbon which aids the macroscopic reading of
results. A reactive result is indicated by agglutination which is
readily visible without the aid of a microscope. Weak- reactive
results can be easily and clearly distinguished from non-reactive
patterns which display a macroscopically smooth and even appearance.
Test results are obtained in 8 minutes.
TPHA
Plasmatec TPHA reagents are used to
detect human serum antibody 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 microtitration plates. Any
non-specific reactions occurring are detected using the Control
Cells, which are avian erythrocytes not coated with T.pallidum
antigens. Non-specific reactions may also be absorbed out using
these Control Cells. Antibodies to non-pathogenic treponemes are
absorbed by an extract of Reiter’s treponemes, included in the cell
suspension. Test results are obtained in 45-60 minutes and the cell
agglutination patterns are both easily read and long lasting.
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