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: Unknown
Which of the following tests are used in the evaluation of a suspected CSF leak? 
Select and explain. 
A. Beta 2 microglobulin, B. Beta 2 transferrin, C. Tyroglobulin, D. Transthyretin
B: Beta 2 transferrin
Answer: B: Beta 2 transferrin 
Explanation: Detection of beta-2 transferrin is considered pa of standard evaluation when CSF leak is suspected. Nasal and ear fluids are tested for detection of the beta-2 transferrin band by immunofixation electrophoresis (IFE) or Western blot analysis as a diagnostic tool for the presence of CSF or perilymph. This test is helpful in the differential diagnosis for CSF otorrhoea or CSF rhinorrhoea. The beta-2 transferrin band has not been detected in multiple fluids including serum, ear fluid, nasal secretions, saliva, tears or endolymph, indicating the specificity of the slower beta-2 transferrin isoform for CSF.