Which marker is used to detect cerebrospinal fluid leakage?

• A. B-trace protein
• B. Beta-2 transferrin
• C. Albumin
• D. Immunoglobulin G

Answer: (A)

CSF leakage is detected by markers that are unique to CSF and absent or very low in peripheral secretions. Beta-trace protein, also called prostaglandin D synthase, is produced in the CNS and is present at high levels in CSF but at negligible levels in serum. When this protein is found in a discharge sample from the nose or ear, it strongly indicates that CSF is present and that a leak is occurring. This makes it a highly useful and specific marker for confirming CSF leakage.

Albumin is a common serum protein, so its appearance in nasal or ear discharge could reflect contamination rather than true CSF origin. Immunoglobulin G is also present in serum and CSF, so its presence in leakage samples lacks CSF-specific confirmation. Beta-2 transferrin is another CSF-specific marker, but beta-trace protein provides a practical and reliable alternative, particularly when transferrin testing isn’t readily available.