Cerebrospinal fluid (CSF) protein concentration
This test measures the total protein content in your cerebrospinal fluid, which is the fluid surrounding your brain and spinal cord. It can help identify issues like inflammation, infections, or blood leaks in the central nervous system.
["Protein levels in CSF may signal neurological conditions requiring further evaluation."]
Key facts at a glance
- LOINC
- 11998-2
- Short code
- ACA-PI-DOPPLER
- Synonyms
- Cerebral a Ant PI DOP
- Category
- chemistry
- Sample
- serum
- Container
- Not applicable – imaging procedure; results documented in radiology/ultrasound report
- Units
- N/A
- Ref low
- 0.6
- Ref high
- 1.1
- Critical range
- 0.4 N/A – 1.4 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- us-doppler
- CPT
- 93886
- SNOMED
- 251056000
- Specimen volume
- Not applicable
- Stability
- Not applicable – real-time ultrasound measurement
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 1–4 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you have symptoms like headaches, neck stiffness, confusion, or neurological problems. It’s also used to diagnose conditions such as meningitis, multiple sclerosis, or brain tumors. Sometimes, it’s part of a routine check if you have a history of neurological disorders.
What to Expect Before the Test
You’ll likely have a small needle inserted into your back to collect CSF. This is usually done in a hospital or clinic setting. You may feel a brief pinch, but the procedure is quick. Avoid strenuous activity for a few hours afterward.
What the Results Mean
Normal protein levels in CSF are generally lower than in blood. Elevated levels might suggest inflammation, infection, or bleeding in the brain. Lower-than-normal levels could indicate certain genetic or metabolic disorders.
Common Conditions Linked to This Test
High protein levels in CSF are often associated with conditions like meningitis, encephalitis, or multiple sclerosis. Low levels may be linked to conditions such as cerebral dysgenesis or certain genetic disorders.
Reference range
Anterior cerebral artery (ACA) Pulsatility Index (PI) reference range: 0.60–1.10. Normal PI values indicate normal cerebrovascular resistance. Values are age-dependent and may increase with advancing age due to reduced vascular compliance.N/A
No special fasting required. Patient should remain still during the examination. Hair gel, lotions, or other scalp products should be removed before the procedure. For transorbital or transtemporal windows, cooperation with breath-holding and positioning instructions is essential. No sedation typically required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CSF Protein Level
Frequently asked questions
What does a high CSF protein level usually indicate?
How is CSF protein tested?
Can lifestyle changes affect CSF protein levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy