DefinitionCSF total protein is a test to determine the amount of protein in cerebrospinal fluid (CSF). CSF is a clear fluid that circulates in the space surrounding the spinal cord. An abnormal protein level in the CSF suggests that there is an abnormal process occurring in the central nervous system.How the test is performedA sample of CSF is needed. A lumbar puncture (spinal tap) is the most common way to collect this sample. For information on this procedure, see the article on lumbar puncture.Other methods for collecting CSF are rarely used, by may be recommended in some cases. They include:Cisternal punctureVentricular punctureRemoval of CSF from a tube that is already in the CSF, such as a shunt or ventricular drain.After the sample is taken, it is sent to a laboratory for evaluation