Any answer with treponemes is used to syphilus only and is very specific. That only leaves cardiolipin, which is also elevated in SLE; this is why its sensitive but not specific in Syph.

Diagnosis of Syph: Visualized by immunofluorescence or dark-field microscopy; serology is important – two types of antibodies:

• Ab binds to cardiolipin: an antigen found in mammalian mitochondrial membranes and in treponemes; a cheap source of antigen is cow heart, which is used in screening tests; very sensitive in primary, except early, and secondary syphilis – titer may decline in tertiary and with treatment; but not specific – must confirm with FTA-ABS.

• Examples include Venereal Disease Research Lab (VDRL), Rapid plasma Reagin (RPR), Automated Reagin Test (ART), or Recombinant Antigen Test (ICE)

• Specific tests for treponemal antibody are more expensive; earliest antibodies bind to spirochetes: these tests are more specific and positive earlier; usually remain positive for life, but positive n patients with other treponemal diseases and may be positive in Mono, RF, Lupus, Leprosy, Lime, and Drug users.

• The most widely used is Fluorescent Treponemal Antibody- Absorption (FTA-ABS) or Treponema pallidum microhemagglutination (MHA-TP)

Non-treponemal tests are sensitive, but not specific - RPR, VRDL