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The Venereal Disease Research Laboratory test (VDRL) is a blood test for syphilis and related non-venereal treponematoses that was developed by the eponymous US laboratory. The VDRL test is used to screen for syphilis (it has high sensitivity ), whereas other, more specific tests are used to diagnose the disease.
Centers for Disease Control and Prevention (CDC)-approved standard tests include the VDRL test (a slide test), the rapid plasma reagin (RPR) test (a card test), the unheated serum reagin (USR) test, and the toluidine red unheated serum test (TRUST). [2] These have mostly replaced the first nontreponemal test, the Wassermann test. [citation needed]
Replacement tests such as the VDRL test and the RPR test, initially based on flocculation techniques (Hinton), have been shown to produce far fewer false positive results. [citation needed] Indeed, the "biologic false positives" of modern tests usually indicate a serious alternate condition, often an autoimmune disease.
If the antibodies interact with the antigen to form immune complexes, called agglutination, then the test is interpreted as positive. However, if too many antibodies that can bind to the antigen are present, then the antigenic sites are coated by antibodies, and few or no antibodies directed toward the pathogen are able to bind more than one ...
The positive control should give a large amount of enzyme activity, while the negative control should give very low to no activity. If the positive control does not produce the expected result, there may be something wrong with the experimental procedure, and the experiment is repeated.
If stronger with the sera adsorbed with guinea-pig kidney, the test is positive. If stronger with the sera adsorbed with ox red cell stroma, the test is negative. If agglutination is absent in both mixtures, the test is negative. A known 'positive' and 'negative' control serum is tested with each batch of test sera. [citation needed]
The vitamin D receptor (VDR also known as the calcitriol receptor) is a member of the nuclear receptor family of transcription factors. [5] Calcitriol (the active form of vitamin D, 1,25-(OH) 2 vitamin D 3) binds to VDR, which then forms a heterodimer with the retinoid-X receptor.
Treponema pallidum, formerly known as Spirochaeta pallida, is a microaerophilic, gram-negative, spirochaete bacterium with subspecies that cause the diseases syphilis, bejel (also known as endemic syphilis), and yaws. [1] It is known to be transmitted only among humans and baboons. [2]