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
[{'content': 'A VDRL reactive mother gave birth to an infant. All of the following would help in determining the risk of transmission to the infant except - \nSelect and explain. \nA. TPHA test on the serum sample of the mother, B. TPHA test on the serum sample of the infant, C. VDRL on the paired serum sample of the infant and mother, D. Time interval between the treatment of the mother and her delivery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: TPHA test on the serum sample of the mother:\nIndicates mother has syphilis. But it doesn’t say about the congenital syphilis. Moreover, TPHA remains elevated even after\xa0treatment. So, an adequately treated mother before 4th month of gestation has a very less risk of transmission but can still have an\xa0elevated TPHA.', 'role': 'assistant'}]