Regarding diagnostic tests for syphilis, true is all except
VDRL test is used for measurement of antibody titers to assess response to treatment.
FTA-ABS is used to confirm diagnosis in clinically suspected syphilis.
TP-PA test is appropriate for population screening for syphilis.
Fourfold decrease in titer is required by 6 months after therapy for primary syphilis.
For population screening for syphilis, VDRL or RPR test is appropriate.