Is there other types of tests for syphilis besides blood?

Yes. If syphilis of the brain is suspected, we will check the cerebrospinal fluid. And sadly, sometimes syphilis is diagnosed only at autopsy, after it has produced its terrible long-term effects. Thankfully, nowadays this is uncommon.
Syphilis is caused. By a bacterium called treponema pallidum. Syphilis can be diagnosed by finding antibodies in the blood, examining for bacteria in samples from open sores under a microscope (primary ; secondary syphilis) or in some cases examination of cerebropsinal fluid via lumbar puncture.