This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Which is false about syphilis - 
Select and explain. 
A. TPI gives definite diagnosis, B. TPHA is earliest to be +ve, C. VDRL is +ve 1 week after appearance of chancre, D. Serologically not different from yaws
B: TPHA is earliest to be +ve
Answer: B: TPHA is earliest to be +ve 
Explanation: Ans. is 'b' i.e., TPHA is earliest to be (+) ye About other options - TPI is a specific treponemal test and gives definite diagnosis. - VDRL test becomes positive 7-10 days after the appearance of primary chancre (3-5 weeks after acquiring the infection.) - All treponemal and nontreponemal serological tests may be positive in nonveneral treponematoses (eg yaws, pinta and endemic syphilis), so can not differentiate nonveneral treponematoses from syphilis.