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: ENT
Diagnostic test for CSF rhinorrhea is ? 
Select and explain. 
A. Beta - 2 microglobulin, B. Beta - 2 transferrin, C. Thyroglobulin, D. Transthyretin
B: Beta - 2 transferrin
Answer: B: Beta - 2 transferrin 
Explanation: Ans. is 'b' i.e., Beta-2 transferrin Beta-2 transferrin is a CSF-specific variant of transferrin and is used as an endogenous marker of CSF leakage. Beta-2 transferrin is formed by loss of sialic acid due to the presence of neuraminidase in the central nervous system. Beta-2 transferrin has also been called CSF-specific transferrin and tau protein.