Presence of which of the following is confirmatory for CSF rhinorrhea?

Ans. is 'b' i.e., b2 transferrin Detection of CSF Leak1) Biochemical tests* Concentrations of Glucose are higher in CSF than in nasal discharge. Glucose value > 30-40 mg% and protein value < 100 mg % (max 200 mg %) support a diagnosis of CSF leak.* Presence of b2 transferrin is the most definitive test for detection of CSF and b2 transferrin assay is the test of choice when a confirmatory test is needed, because of high sensitivity as well as specificity.* b-trace protein (prostaglandin D synthase) is also used, however it is nonspecific as it is also present in human testes, heart and seroma.2) Basic clinical tests* Tissue test (Handker chief test): - Unlike nasal mucous, CSF does not cause a tissue to stiffen.* Filter paper test: - Sample of nasal discharge on a filter paper exhibits a light CSF border and a dark central area of blood, i.e., double ring sign or halo sign.* Queckensted test: - Compression of the jugular vein leas to increased CSF leak due to increase in ICP.* Rhinoscopy: - Visualization of CSF leak from paranasal sinus.3) CSF tracers* Intrathecal fluorescein dye adminstration, radionuclide cisternography, CT cisternography.