Syphilis dark field microscopy


 * Dark field microscopy may be performed in cases wherein serologic tests do not correspond with clinical findings suggestive of early syphilis.


 * It may also be helpful in the evaluation of cutaneous lesions such as chancre or condylomata lata.


 * Direct fluorescent antibody (DFA-TP) assay of fixed smears may be indicated if dark field microscopy is not available.


 * Dark field microscopy and DFA-TP assay have a specificity rate of 85-92%

Resources

 * Sexually transmitted diseases treatment guidelines, 2010


 * Association of Public Health Laboratories (APHL). Laboratory Diagnostic Testing for Treponema pallidum. Expert Consultation Meeting Summary Report, January 13--15, 2009, Atlanta, GA


 * CDC: Guidelines for the laboratory diagnosis of gonorrhea, chlamydia and syphilis