A tau protein test is used to confirm whether cerebrospinal fluid is leaking from the brain. CSF is a colourless fluid that surrounds the brain and spinal cord.
Following a head injury, such as a skull fracture, the membranes that cover your brain and spine could tear. CSF can leak out through the tear, causing a watery discharge from your ear or nose.
As tau protein is only found in CSF, testing for it will help rule out other types of fluids such as nasal secretions and other body fluids.
Read more about the tau protein test at Lab Tests Online UK.