Cerebrospinal Fluid Output Measurement (24-Hour Total)
This test measures the total volume of fluid collected from your cerebrospinal fluid (CSF) drain over a 24-hour period. It helps assess how well your body is draining fluid from the spaces around your brain and spinal cord.
["Understanding your CSF drainage helps diagnose and monitor conditions affecting fluid balance in the central nervous system."]
Key facts at a glance
- LOINC
- 9128-0
- Short code
- Fluid output subarachnoid drain
- Synonyms
- Fluid output subarachnoid drain
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you have a condition like hydrocephalus (excess CSF), a shunt or drain in place, or symptoms such as headaches, nausea, or neurological issues that suggest abnormal fluid buildup or drainage. It’s also used to monitor drainage efficiency after surgery or trauma.
What to Expect Before the Test
You’ll likely have a catheter or drain inserted into your CSF space (e.g., lumbar puncture or ventricular catheter). Fluid will be collected continuously over 24 hours. You may need to stay in a hospital setting for this process, with instructions to stay hydrated and avoid certain activities.
During the Test
The collected fluid is measured and recorded. The test itself doesn’t require fasting or special preparation beyond following your provider’s instructions. You may be asked to keep a log of intake/output or report any changes in symptoms.
What the Results Mean
Results help determine if your CSF drainage is working as intended. Abnormally low output could indicate blockages or reduced fluid production, while abnormally high output might signal overproduction or leaks. Your provider will interpret results in the context of your medical history and symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is critical for diagnosing and managing conditions like idiopathic intracranial hypertension (pseudotumor cerebri), brain tumors, infections (e.g., meningitis), or post-surgical complications. It ensures your drainage system is functioning properly to prevent complications such as swelling, pressure buildup, or neurological deficits.
Short name
24-Hour CSF Fluid Output
Frequently asked questions
How long does the 24-hour fluid collection last?
Can I eat or drink normally during the test?
What if I experience side effects like headaches or dizziness during the drain?
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