Veneral Disease Resarch Laboratory(VDRL)TEST
AIMS OF TEST
to diagnosis of syphillis
syphillis caused by Treponemal .pallidum
VDRL test is screening test for the presence of reagin,antibody specific for treponemal spirochetes
what mean with reagin
it is mean this test does not look for antibodies against the actual bacterium,but rather fo antibodies against substances released by cells when they ar damaged byTreponema.Pallidum
Types of VDRL test
AIMS OF TEST
to diagnosis of syphillis
syphillis caused by Treponemal .pallidum
VDRL test is screening test for the presence of reagin,antibody specific for treponemal spirochetes
what mean with reagin
it is mean this test does not look for antibodies against the actual bacterium,but rather fo antibodies against substances released by cells when they ar damaged byTreponema.Pallidum
Types of VDRL test
- VDRL-Serum
VDRL-CSF sample obtained by lumber punctur
principle
heated serum or unheated CSF is mixedwith antigen to reagin on glass slide
Antigen is purified mixture of lipid such as
cardiolipin,lecithin,and cholestrol
this mixture examined microscopillay to detect the clumping of the mixture
RESULTS
-REACTIVE(positive)clumping occure
-NON-REACTIVE(negative)no clumping
VDRL test usually become reactive within the first weeks after infection
VDRL test can fail to show reactive results in the late stage of syphillis
VDRLtest less sensitive than PRP test for primary syphillis
false positive results are caused by the following factors
principle
heated serum or unheated CSF is mixedwith antigen to reagin on glass slide
Antigen is purified mixture of lipid such as
cardiolipin,lecithin,and cholestrol
this mixture examined microscopillay to detect the clumping of the mixture
RESULTS
-REACTIVE(positive)clumping occure
-NON-REACTIVE(negative)no clumping
VDRL test usually become reactive within the first weeks after infection
VDRL test can fail to show reactive results in the late stage of syphillis
VDRLtest less sensitive than PRP test for primary syphillis
false positive results are caused by the following factors
- malaria
- measles
- lupus erythematosis
- leprosis
- hepatitis
- Lyme diseae
refrigeration for 72hours destoyes the treponemal spirochetes
a person may negative VDRL test and still have syphillis inthe early stages of disease
positive results confirmed by (FTA-Abs DS)Test
Fluorescence Treponemal Antibody-Absorption double stain test
this test provide the most sensetive detection of treponemal antibodies for syphillis in all stages
in this test
serum treated to remove antibodies that could cause false-positive results
this techniqe involve fluorescence microscope with special filters that decrease the amount of natural fluorescence from background of the spicemen
fluorescein-conjugated antibodies to IgG are added as counterstain to the stained the spicemen
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