VDRL is a: September 2010, March 2011
**Core Concept**
The Venereal Disease Research Laboratory (VDRL) test is a type of nontreponemal serologic test used for the screening and diagnosis of syphilis. It detects the presence of non-treponemal antibodies, which are produced in response to the infection.
**Why the Correct Answer is Right**
The VDRL test measures the levels of cardiolipin antibodies in the blood, which are produced in response to the infection. These antibodies are a result of the host's immune response to the lipid antigens released from the damaged host cells. The VDRL test uses cardiolipin as an antigen to detect these antibodies. The results are reported as a titer, with higher titers indicating a more severe infection.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the VDRL test is not a treponemal test, which specifically detects antibodies against the Treponema pallidum bacteria.
**Option B:** This option is incorrect because the Rapid Plasma Reagin (RPR) test is another type of nontreponemal test, but it is not the correct answer.
**Option C:** This option is incorrect because the Fluorescent Treponemal Antibody Absorption (FTA-ABS) test is a treponemal test used for the diagnosis of syphilis, but it is not the correct answer.
**Clinical Pearl / High-Yield Fact**
The VDRL test is a screening test, and a positive result should be confirmed with a treponemal test, such as the FTA-ABS test, to confirm the diagnosis of syphilis.
**Correct Answer: D**