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The Venereal Disease Research Laboratory test (VDRL) is a blood test for
syphilis Syphilis () is a sexually transmitted infection caused by the bacterium ''Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms of syphilis vary depending in which of the four stages it presents (primary, secondary, latent, an ...
and related non-venereal
treponematoses Treponematosis is a term used to individually describe any of the diseases caused by four members of the bacterial genus ''Treponema''. The four diseases are collectively referred to as treponematoses: * Syphilis (''Treponema pallidum pallidum'') * ...
that was developed by the eponymous lab. The VDRL test is used to screen for syphilis (it has high sensitivity), whereas other, more
specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the fina ...
tests are used to diagnose the disease.


History

The VDRL type test was invented before
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, with its first iteration being that developed by
August Paul von Wasserman August Paul von Wassermann (21 February 1866 – 16 March 1925) was a German bacteriologist and hygienist. Born in Bamberg, with Jewish origins, he studied at several universities throughout Germany, receiving his medical doctorate in 1888 from ...
with the aid of Albert Neisser in 1906. The VDRL test, as it is largely still done today, was developed in 1946 by Harris, Rosenberg, and Riedel. The lab was renamed to the
Treponemal Pathogenesis and Immunology Branch ''Treponema'' is a genus of Spiral bacteria#Spirochete, spiral-shaped bacteria. The major treponeme species of human pathogens is ''Treponema pallidum'', whose subspecies are responsible for diseases such as syphilis, bejel, and yaws. ''Treponem ...
of the
United States Public Health Service The United States Public Health Service (USPHS or PHS) is a collection of agencies of the Department of Health and Human Services concerned with public health, containing nine out of the department's twelve operating divisions. The Assistant S ...
.


Mechanism

The VDRL is a
nontreponemal A nontreponemal test (NTT) is a blood test for diagnosis of infection with syphilis. Nontreponemal tests are an indirect method in that they detect biomarkers that are released during cellular damage that occurs from the syphilis spirochete. In ...
serological screening for
syphilis Syphilis () is a sexually transmitted infection caused by the bacterium ''Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms of syphilis vary depending in which of the four stages it presents (primary, secondary, latent, an ...
that is also used to assess response to therapy, to detect
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
involvement, and as an aid in the diagnosis of congenital syphilis. The basis of the test is that an antibody produced by a patient with syphilis reacts with an extract of ox heart (diphosphatidyl glycerol). It therefore detects
anti-cardiolipin antibodies Anti-cardiolipin antibodies (ACA) are antibodies often directed against cardiolipin and found in several diseases, including syphilis, antiphospholipid syndrome, livedoid vasculitis, vertebrobasilar insufficiency, Behçet's syndrome, idiopathic s ...
(IgG, IgM or IgA), visualized through foaming of the test tube fluid, or "flocculation". The
rapid plasma reagin The rapid plasma reagin test (RPR test or RPR titer) is a type of rapid diagnostic test that looks for non-specific antibodies in the blood of the patient that may indicate an infection by syphilis or related non-venereal treponematoses. It is on ...
(RPR) test uses the same antigen as the VDRL, but in that test, it has been bound to several other molecules, including a carbon particle to allow visualization of the flocculation reaction without the need of a microscope. Many other medical conditions can produce false positive results, including some viruses (mononucleosis, hepatitis), drugs, pregnancy, rheumatic fever, rheumatoid arthritis, lupus, and leprosy. The syphilis anti-cardiolipin antibodies are beta-2 glycoprotein independent, whereas those that occur in
antiphospholipid syndrome Antiphospholipid syndrome, or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by antiphospholipid antibodies. APS provokes blood clots (thrombosis) in both arteries and veins as well as pregnancy- ...
(associated to lupus for example) are beta-2 glycoprotein dependent, and this can be used to tell them apart in an
ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence ...
assay. This test is very useful as the trend of titres are correlated to disease activity (i.e. falling titres indicate successful treatment). It has a very good sensitivity for syphilis, except in late tertiary form.


Other tests

There are a number of treponemal-specific tests such as the fluorescent treponemal antibody-absorption (
FTA-ABS The fluorescent treponemal antibody absorption (FTA-ABS) test is a diagnostic test for syphilis. Using antibodies specific for the ''Treponema pallidum'' species, such tests would be assumed to be more specific than non-treponemal testing such as ...
) test, ''T. pallidum'' hemagglutination assays (
TPHA The ''Treponema pallidum'' particle agglutination assay (also called TPPA test) is an indirect agglutination assay used for detection and titration of antibodies against the causative agent of syphilis, ''Treponema pallidum'' subspecies ''pallid ...
), and the microhemagglutination assay ( MHA-TP). The MHA-TP is used to confirm a syphilis infection after another method tests positive for the syphilis bacteria. The MHA-TP test detects antibodies to the bacteria that cause syphilis and can be used to detect syphilis in all stages, except during the first 3 to 4 weeks. This test is not done on spinal fluid. The MHA-TP test is rarely used any more. Treponema pallidum particle agglutination assay ( TP-PA) and the Toluidine red unheated serum test (TRUST), which may be used to confirm a positive VDRL result, are more
specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the fina ...
for syphilis than non-treponemal tests and in the presence of a positive test, more likely indicate active infection. Unfortunately, other treponemal infections such as
yaws Yaws is a tropical infection of the skin, bones, and joints caused by the spirochete bacterium ''Treponema pallidum pertenue''. The disease begins with a round, hard swelling of the skin, in diameter. The center may break open and form an ulce ...
,
bejel Bejel, or endemic syphilis, is a chronic skin and tissue disease caused by infection by the ''endemicum'' subspecies of the spirochete ''Treponema pallidum''. Bejel is one of the "endemic treponematoses" (endemic infections caused by spiral-shaped ...
, and pinta and possibly nonpathogenic commensal treponemes can result in a positive. Not all these disease are venereal; it has been recommended that a careful explanation of this fact be included with test results.


References

{{DEFAULTSORT:Venereal Disease Research Laboratory Test Infectious disease blood tests Syphilis