Which test detects Treponema pallidum DNA in body fluids?

Which test detects Treponema pallidum DNA in body fluids?

• A. VDRL test
• B. RPR test
• C. PCR testing of Treponema pallidum DNA
• D. Darkfield microscopy of lesions

Answer: (C)

Detecting Treponema pallidum DNA in body fluids is done with a molecular method that amplifies the bacterium’s genetic material, making direct and specific identification possible from samples such as blood, CSF, or lesion fluid. This approach, PCR, targets unique DNA sequences of the organism, so a positive result confirms the presence of the pathogen itself rather than just an immune response. VDRL and RPR are non-treponemal antibody tests. They detect reagin antibodies to cardiolipin and can yield false positives from other conditions and various stage-related limitations; they don’t detect the organism’s DNA and can’t confirm the infection at the DNA level. Darkfield microscopy can visualize spirochetes in fresh lesion exudate but requires appropriate lesions and skilled technique, and it doesn’t provide DNA-based confirmation or routine testing for all body fluids.

Detecting Treponema pallidum DNA in body fluids is done with a molecular method that amplifies the bacterium’s genetic material, making direct and specific identification possible from samples such as blood, CSF, or lesion fluid. This approach, PCR, targets unique DNA sequences of the organism, so a positive result confirms the presence of the pathogen itself rather than just an immune response.

VDRL and RPR are non-treponemal antibody tests. They detect reagin antibodies to cardiolipin and can yield false positives from other conditions and various stage-related limitations; they don’t detect the organism’s DNA and can’t confirm the infection at the DNA level. Darkfield microscopy can visualize spirochetes in fresh lesion exudate but requires appropriate lesions and skilled technique, and it doesn’t provide DNA-based confirmation or routine testing for all body fluids.