diagnosis 1.sexual contact 2.Clinical feature Latent period,typical chancre However,many syphilitic ulcers are not typical and any ulcer appearing on the genitalia should be suspect. 3.Laboratory test darkfield examination positive STS diagnosis 1. sexual contact 2. Clinical feature - Latent period, typical chancre - However, many syphilitic ulcers are not typical and any ulcer appearing on the genitalia should be suspect. 3. Laboratory test - darkfield examination - positive STS