diagnosis 1.History:sexual contact,chancre 2.Clinical feature -skin rash 3.Laboratory test -darkfield microscopic examination:skin or mucous membrane lesions,condyloma lata positive STSdiagnosis 1. History: sexual contact, chancre 2. Clinical feature -skin rash 3. Laboratory test - darkfield microscopic examination: skin or mucous membrane lesions, condyloma lata - positive STS