I Was Tested Syphilis Positive During A Health Check, Whereas,

I was tested syphilis positive during a health check, whereas, it was found negative just 3 months before this test. I was suggested to take 3 doses of penicillin(weekly once) by a doctor in china. I have completed treatment and 2 week later the 3rd dose I went for blood test to check the presence of anti-bodies(I do not have clear idea of it), doctor read the report and said infection in my blood has 'gone' but to get a VDRL test negative I may need to wait for 6-8 months.
My questions are:
1. If VDRL comes to be negative after 6-8 months, does it mean test for Syphilis is negative?
2. When we are overseas and get blood test done, especially in countries like Middle east and China , what factor do they test to detect syphilis in the preliminary tests
3. What is the normal range of this factor to detect Syphilis in blood to rule out presence of syphilis?
Thanks a lot in advance