At a Glance
Why Get Tested?
To help identify cerebrospinal fluid (CSF) leaking from the skull.
When to Get Tested?
If there is a watery discharge from your nose or ear (rhinorrhoea or otorrhoea) after you have suffered a skull fracture or after brain surgery.
A sample of the suspicious watery discharge is collected into a plastic tube and at the same time a blood sample is also collected.
Test Preparation Needed?
The Test Sample
What is being tested?
Cerebrospinal fluid (CSF) is normally found only within the brain and the spinal canal. If you suffer an injury which causes a tear in the membranes covering the brain and spine, CSF may leak out. This may sometimes cause watery fluid to drip from either the nose or the ear (rhinorrhoea or otorrhoea). Distinguishing CSF from other watery discharge involves looking for the presence of something which would normally only be found in CSF. Tau protein is beta 2 transferrin. This form of transferrin is present in CSF but not usually found in blood, nasal secretions or other body fluids. The suspect sample should be examined along with a serum sample to confirm results.
How is the sample collected for testing?
The suspicious watery discharge will be collected into a plain plastic tube. A sample of blood will also be taken from a vein in your arm at the same time.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.