This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
A newborn premature baby presented with bullous lesions on skin and legs, Xray shows features suggestive of periostitis. Which of the following is the initial investigation? 
Select and explain. 
A. VDRL test, B. FTA-ABS test, C. TPHA test, D. culture
A: VDRL test
Answer: A: VDRL test 
Explanation: The newborn baby has characteristic signs and symptoms of congenital syphilis. Periostitis is a hallmark of skeletal manifestation. VDRL/RPR is the initial investigation of choice in congenital syphilis. All neonates born to mothers who have reactive nontreponemal and treponemal test results should be evaluated with a quantitative nontreponemal serologic test (RPR or VDRL) performed on the neonate's serum, because umbilical cord blood can become contaminated with maternal blood and yield a false-positive result. FTA-ABS/TPHA are used for confirmation of syphilis in a patient with reactive RPR/VDRL test. T. pallidum cannot be detected by culture. Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition