Is it possible to have a false negative syphilis test?

Yes. Testing for syphilis can sometimes be a complicated process which requires expert interpretation. Unfortunately there is no test in medicine which is 100% accurate 100% of the time. A false negative syphilis test may occur within the first 2 weeks after the common syphilis ulcer appears. Patients with immune disorder such as HIV and aids may also test falsely negative for syphilis.