Platform
Company
Body Fluids
Review status
Currently under review
Pending specialist review and validation.
The Protein CSF test measures the amount of protein in your cerebrospinal fluid, the clear liquid that cushions and protects your brain and spinal cord. The sample is collected during a lumbar puncture, also called a spinal tap, performed by a clinician under sterile conditions.
Proteins can enter cerebrospinal fluid from the blood or be produced within the central nervous system. Changes in CSF protein can reflect how well the blood–brain barrier is working, whether there is inflammation or bleeding, and whether there is blockage of CSF flow. This test is usually interpreted together with other CSF studies such as cell counts, glucose, cultures, and specific markers.
Clinicians use CSF protein to help evaluate symptoms such as severe headache, fever with neck stiffness, confusion, seizures, weakness, or sensory changes. It can support the diagnosis of infections like meningitis, inflammatory or autoimmune conditions, nerve root disorders, bleeding around the brain, and problems that obstruct CSF flow.
Knowing whether CSF protein is higher or lower than expected, and how it compares with other CSF results, can guide urgent treatment decisions, the need for imaging, and follow‑up testing. It can also help monitor response to therapy for certain neurologic conditions.
Your result will be interpreted in the context of your age, symptoms, exam findings, and other laboratory and imaging tests. A higher CSF protein can occur with inflammation, infection, spinal block, bleeding into the CSF, or some tumors, while a lower value can be seen with CSF leaks or overdrainage. The collection site and timing relative to symptom onset can also influence results.
Small amounts of blood introduced during a difficult lumbar puncture can artificially raise the protein measurement. Laboratories and clinicians consider this possibility by reviewing the red blood cell count in the sample and the overall pattern of findings. If results are unexpected, your clinician may correlate with other CSF indices, repeat testing if contamination is suspected, or order targeted imaging or specialist consultation.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Accidental bleeding during the lumbar puncture can release proteins from blood into the sample, falsely increasing the measured CSF protein. Your clinician will consider the red blood cell count to assess this effect.
CSF should be collected into the recommended sterile tubes and promptly delivered to the laboratory. Delays, incorrect tubes, or significant hemolysis may subtly alter protein measurements and complicate interpretation.
Normal CSF protein varies with age, and infants naturally have higher values than older children and adults. Laboratories use age‑appropriate interpretation when reporting results.
Conditions that obstruct CSF flow or cause inflammation along nerve roots, such as tumors or severe radiculitis, can raise protein measured in lumbar samples without widespread infection.
Recent spinal surgery, anesthesia, contrast administration, or intrathecal therapies can change CSF composition and may increase protein for a period after the procedure.
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