Biochemical Investigations

In patients with nasal injury and persisting discharge from the nose, it can be difficult to differentiate between nasal secretion and cerebrospinal fluid (CSF) arising from a nasoethmoidal fracture.

Although often advocated, testing for the presence of glucose, which is present in CSF but not normally in nasal secretion, may be falsely positive due to contamination of nasal secretions by blood or tears.

Beta-2 transferrin (also known as the Tau protein) is almost exclusively found in CSF and is a highly sensitive and specific test for the presence of CSF [15].

Learning bite

The presence of beta-2 transferrin in nasal discharge is the most accurate diagnostic test to confirm CSF rhinorrhoea.