What is a CSF analysis?
Cerebrospinal fluid (CSF) analysis is a way of looking for conditions that affect your brain and spine. It’s a series of laboratory tests performed on a sample of CSF. CSF is the clear fluid that cushions and delivers nutrients to your central nervous system (CNS). The CNS consists of the brain and spinal cord.
CSF is produced by the choroid plexus in the brain and then reabsorbed into your bloodstream. The fluid is completely replaced every few hours. In addition to delivering nutrients, CSF flows around your brain and spinal column, providing protection and carrying away waste.
A CSF sample is commonly collected by performing a lumbar puncture, which is also known as a spinal tap. An analysis of the sample involves the measurement of and examination for:
- fluid pressure
- red blood cells
- white blood cells
- other invasive organisms or foreign substances
Analysis can include:
- measurement of the physical characteristics and appearance of CSF
- chemical tests on substances found in your spinal fluid or comparisons to levels of similar substances found in your blood
- cell counts and typing of any cells found in your CSF
- identification of any microorganisms that could cause infectious diseases
CSF is in direct contact with your brain and spine. So CSF analysis is more effective than a blood test for understanding CNS symptoms. However, it’s more difficult to obtain a spinal fluid sample than a blood sample. Entering the spinal canal with a needle requires expert knowledge of the spine’s anatomy and a clear understanding of any underlying brain or spinal conditions that might increase the risk of complications from the procedure.
A lumbar puncture generally takes less than 30 minutes. It’s performed by a doctor who is specially trained to collect CSF.
CSF is usually taken from your lower back area, or the lumbar spine. It’s very important to remain completely still during the procedure. This way you avoid incorrect needle placement or trauma to your spine.
You may be seated and asked to lean over so that your spine is curled forward. Or your doctor may have you may lie on your side with your spine curved and your knees drawn up to the chest. Curving your spine makes a space between your bones in the lower back.
Once you’re in position, your back is cleaned with a sterile solution. Iodine is often used for cleaning. A sterile area is maintained throughout the procedure. This reduces the risk of infection.
A numbing cream or spray is applied to your skin. Your doctor then injects anesthetic. Once the site is fully numb, your doctor inserts a thin spinal needle between two vertebrae. A special type of X-ray called fluoroscopy is sometimes used to guide the needle.
First, the pressure inside the skull is measured using a manometer. Both high and low CSF pressure can be signs of certain conditions.
Fluid samples are then taken through the needle. When fluid collection is complete, the needle is removed. The puncture site is cleaned again. A bandage is applied.
You’ll be asked to remain lying down for about one hour. This reduces the risk of a headache, which is a common side effect of the procedure.
Sometimes a person can’t have a lumbar puncture because of a back deformity, infection, or possible brain herniation. In these cases, a more invasive CSF collection method that requires hospitalization might be used, such as one of the following:
- During a ventricular puncture, your doctor drills a hole into your skull and inserts a needle directly into one of the ventricles of your brain.
- During a cisternal puncture, your doctor inserts a needle into the back of your skull.
- A ventricular shunt or drain can collect CSF from a tube that your doctor places in your brain. This is done to release high fluid pressure.
CSF collection is often combined with other procedures. For example, dye might be inserted into your CSF for a myelogram. This is an X-ray or CT scan of your brain and spine.
This test requires a signed release that states you understand the risks of the procedure.
Primary risks associated with lumbar puncture include:
- bleeding from the puncture site into the spinal fluid, which is called a traumatic tap
- discomfort during and after the procedure
- an allergic reaction to the anesthetic
- an infection at the puncture site
- a headache after the test
People who take blood thinners have a heightened risk of bleeding. Lumbar puncture is extremely dangerous for people who have clotting problems such as a low platelet count, which is called thrombocytopenia.
There are serious additional risks if you have a brain mass, tumor, or abscess. These conditions put pressure on your brain stem. A lumbar puncture could then cause brain herniation to occur. This can result in brain damage or even death.
Brain herniation is a shifting of structures of the brain. It’s usually accompanied by high intracranial pressure. The condition eventually cuts off blood supply to your brain. This causes irreparable damage. The test won’t be done if a brain mass is suspected.
Cisternal and ventricular puncture methods carry additional risks. These risks include:
- damage to your spinal cord or brain
- bleeding within your brain
- disturbance of the blood-brain barrier
CSF analysis may be ordered if you’ve had CNS trauma. It may also be used if you have cancer and your doctor wants to see if the cancer has spread to the CNS.
In addition, CSF analysis may be ordered if you have one or more of the following symptoms:
- severe, unremitting headache
- stiff neck
- hallucinations, confusion, or dementia
- flu-like symptoms that persist or intensify
- fatigue, lethargy, or muscle weakness
- changes in consciousness
- severe nausea
- fever or rash
- light sensitivity
- numbness or tremor
- speaking difficulties
- trouble walking or poor coordination
- severe mood swings
- intractable clinical depression
(Video) Cerebrospinal Fluid (CSF) Review
CSF analysis can accurately distinguish between a wide range of CNS diseases that can otherwise be difficult to diagnose. Conditions found by CSF analysis include:
Viruses, bacteria, fungi, and parasites can all infect the CNS. Certain infections can be found by CSF analysis. Common CNS infections include:
- fungal infections
- West Nile virus
- eastern equine encephalitis virus (EEEV)
Intracranial bleeding can be detected by CSF analysis. However, isolating the exact cause of bleeding may require additional scans or tests. Common causes include high blood pressure, stroke, or an aneurysm.
Immune response disorders
CSF analysis can detect immune response disorders. The immune system can cause damage to the CNS through inflammation, destruction of the myelin sheath around the nerves, and antibody production.
Common diseases of this type include:
- Guillain-Barré syndrome
- multiple sclerosis
CSF analysis can detect primary tumors in the brain or spine. It can also detect metastatic cancers that have spread to your CNS from other body parts.
CSF analysis may also be used to help diagnose multiple sclerosis (MS). MS is a chronic condition in which your immune system destroys the protective covering of your nerves, which is called myelin. People with MS may have a variety of symptoms that are constant or come and go. They include numbness or pain in their arms and legs, vision problems, and trouble walking.
CSF analysis may be done to rule out other medical conditions that have symptoms similar to MS. The fluid may also show signs that your immune system isn’t functioning normally. This can include high levels of IgG (a type of antibody) and the presence of certain proteins that form when myelin breaks down. About 85 to 90 percent of people with MS have these abnormalities in their cerebral spinal fluid.
Some types of MS progress quickly and can be life-threatening within weeks or months. Looking at the proteins in CSF may enable doctors to develop “keys” called biomarkers. Biomarkers can help identify the type of MS you have earlier and more easily. Early diagnosis could allow you to get treatment that could extend your life if you have a form of MS that’s rapidly progressing.
The following are often measured in CSF analysis:
- white blood cell count
- red blood cell count
- glucose, or blood sugar
- lactate dehydrogenase, which is a blood enzyme
- antigens, or harmful substances produced by invading microorganisms
- total proteins
- oligoclonal bands, which are specific proteins
- cancer cells
- viral DNA
- antibodies against viruses
Normal results mean that nothing abnormal was found in the spinal fluid. All measured levels of CSF components were found to be within normal range.
Abnormal results may be caused by one of the following:
- a tumor
- metastatic cancer
- encephalitis, which is an inflammation of the brain
- an infection
- Reye’s syndrome, which is a rare, often fatal disease affecting children that’s associated with viral infections and aspirin ingestion
- meningitis, which you can get from fungi, tuberculosis, viruses, or bacteria
- viruses such as West Nile or Eastern equine
- Guillain-Barré syndrome, which is an autoimmune condition that causes paralysis and occurs after viral exposure
- sarcoidosis, which is a granulomatous condition of unknown cause affecting many organs (primarily the lungs, joints, and skin)
- neurosyphilis, which happens when an infection with syphilis involves your brain
- multiple sclerosis, which is an autoimmune disorder that affects your brain and spinal cord
(Video) CSF Analysis in Meningitis
Your follow-up and outlook will depend on what caused your CNS test to be abnormal. Further testing will most likely be required in order to get a definitive diagnosis. Treatment and outcomes will vary.
Meningitis caused by a bacterial or parasitic infection is a medical emergency. Symptoms are similar to viral meningitis. However, viral meningitis is less life-threatening.
People with bacterial meningitis may receive broad-spectrum antibiotics until the cause of the infection is determined. Prompt treatment is essential to save your life. It can also prevent permanent CNS damage.
How many drops of CSF is enough?
|Test||Volume of CSF required in drops per sample|
|Bacteriology*||3||At least 3|
|TB||3||As much as practical|
|Viral culture||3||As much as practical|
When this fluid volume is reduced, there is less fluid available to cushion the brain inside the skull. This loss of CSF causes headache and other neurological signs and symptoms and may result in a range of complications. With upright posture, the loss of CSF volume has a greater effect on the brain.What are possible findings on CSF studies? ›
In general, your CSF analysis results may show that you have an infection, an autoimmune disorder, such as multiple sclerosis (MS), or another disease or injury of the brain or spinal cord. Your provider will likely order more tests to confirm your diagnosis.How to interpret CSF fluid analysis? ›
- Appearance: Clear.
- Opening pressure: 10-20 cmCSF.
- WBC count: 0-5 cells/µL. < 2 polymorphonucleocytes [PMN]) ...
- Glucose level: >60% of serum glucose.
- Protein level: < 45 mg/dL.
- Consider additional tests: CSF culture, others depending on clinical findings.
A total of 8 to 15 mL of CSF is typically removed during routine LP.How many drops of CSF do I need for a lumbar puncture? ›
If CSF is flowing: collect into 2-3 numbered sterile tubes. 5-10 drops in each is usually adequate, but more may be required depending on investigations ordered. 20 drops = 1 mL.What does low CSF feel like? ›
What are the symptoms of low pressure headaches? The classic symptom is a headache that becomes severe when the patient is upright and quickly disappears when the patient is lying flat. So, the headaches are typically absent first thing in the morning, and start or worsen shortly after getting out of bed.What does low intracranial pressure feel like? ›
Intracranial Hypotension Symptoms
Nausea, with or without vomiting. Neck pain or stiffness. Hearing changes, such as muffled hearing or ringing in the ears. Difficulty concentrating.
Intracranial hypotension (ICH) is defined as a CSF pressure less than 60 mm H2O and generally causes a postural headache in patients with the condition.How long does it take for spinal fluid to replenish? ›
CSF is produced at a rate of around 500 ml/day; there are estimates that there is approximately 125 mL to 150 mL of CSF in the body at any given time. Depending on the rate of production and absorption (which varies individually), the supply of CSF can be replaced about every 7.5 hours.
Analysis of the CSF provides invaluable diagnostic information because diseases take place either within its bounding membranes (e.g., meningitis) or in the adjoining parameningeal structures of the brain (e.g., brain abscess).What is the most confirmatory test for CSF leak? ›
Myelography. This test is considered the gold standard for diagnosing and locating CSF leaks. It uses digital subtraction fluoroscopy, a CT or MRI scan, and a contrast dye to locate CSF leaks. It provides the most precise location of a CSF leak and helps to determine the most appropriate treatment plan.What are the CSF findings in multiple sclerosis patients? ›
The CSF is clear and colorless in all patients with MS, and most patients have normal cell counts and total protein levels. Even during an acute exacerbation, total CSF protein and cell counts remain normal, although sometimes a modest mononuclear pleocytosis can be identified.Can you have MS with a negative spinal tap? ›
However, you cannot 100 percent confirm or rule out MS based on a spinal tap, explains Dr. Giesser. “Even if the spinal tap is negative, about 10 percent of people who have MS have normal spinal fluid. And if it's positive, other things [other than MS] can cause a positive result,” she says.What is the normal range for CSF cells? ›
|CSF WBC count||0–8 leukocytes/mm|
|CSF RBC count||<1 RBC/mm|
|CSF protein||15–45 mg/dL||L|
An abnormal protein level in the CSF suggests a problem in the central nervous system. Increased protein level may be a sign of a tumor, bleeding, nerve inflammation, or injury. A blockage in the flow of spinal fluid can cause the rapid buildup of protein in the lower spinal area.What does white blood cells in spinal fluid mean? ›
An increase of white blood cells indicates infection, inflammation, or bleeding into the cerebrospinal fluid. Some causes include: Abscess. Encephalitis. Hemorrhage.At what level is a spinal tap performed to prevent damage to the spinal cord? ›
A spinal tap is done in the lower lumbar area, below the point where the spinal cord ends. So, the risk of harming the spinal cord is avoided. A spinal tap is not surgery.How many samples are needed for a lumbar puncture? ›
CSF taken by lumbar puncture (CSF LP)
Four samples of CSF should be collected into clearly labelled sterile containers, which indicate the sequence order of sampling. Sample 2 (0.5 mL minimum) should be in a fluoride/oxalate tube for glucose. Samples 1, 3 and 4 (each 1.5 mL minimum) should be in plain sterile tubes.
A common excuse for an unsuccessful LP in a large patient is that the standard (3.5-in) needle is too short. Although a number of articles discuss the technique of performing LPs,1,2 we could find no previous studies that actually measured the distance from the skin to the thecal sac.
Excessive CSF drainage or persistent leakage through the dural puncture site can lead to cerebral hypotension and creation of an intracranial subdural hematoma.Can you have low CSF without a leak? ›
Low CSF pressure without a leak being found, called "spontaneous intracranial hypotension", is rare, with a yearly incidence of about 5/100,000. These may be dectected from dural enhancement or lumbar puncture.What does a CSF headache feel like? ›
A headache that is worse when you sit up and improves when you lie down. It may be associated with light sensitivity, nausea, and neck stiffness. Drainage of CSF from the ear (rarely).Can a CSF leak go unnoticed? ›
Although CSF leaks may not be readily apparent on imaging, a suspected CSF leak is important to consider because it is fixable, said Dr. Carroll, Assistant Professor of Anesthesiology and Perioperative and Pain Medicine at Stanford University Medical Center in California and a member of the Stanford CSF leak program.What are the three main signs of increased intracranial pressure? ›
Clinical suspicion for intracranial hypertension should be raised if a patient presents with the following signs and symptoms: headaches, vomiting, and altered mental status varying from drowsiness to coma.What are the symptoms of a sagging brain? ›
When the fluid leaks out, the volume and pressure of fluid in your skull drops, leading your brain to slump. "This 'brain sag' can trigger severe, relentless headaches, and can also cause vision and hearing disturbances, seizures and other symptoms such as neck pain and a heightened sense of smell," explains Wouter I.What are the four stages of intracranial pressure? ›
Intracranial hypertension is classified in four forms based on the etiopathogenesis: parenchymatous intracranial hypertension with an intrinsic cerebral cause, vascular intracranial hypertension, which has its etiology in disorders of the cerebral blood circulation, meningeal intracranial hypertension and idiopathic ...Can dehydration cause low CSF? ›
Historically, dehydration was considered a mechanism for spontaneous CSF hypotension due to reduced blood flow and subsequent reduction CSF secretion .What is normal CSF values in age? ›
The 95th percentile values were 116 mg/dL for infants 0 to 28 days and 80 mg/dL for infants 29 to 56 days. The 95th percentile values by age category were as follows: ages 0 to 14 days, 117 mg/dL; ages 15 to 28 days, 107 mg/dL; ages 29 to 42 days, 96 mg/dL; and ages 43 to 56 days, 74 mg/dL.Can low CSF cause back pain? ›
Back pain, limb pain, and limb numbness were inversely associated with CSF leaks (p = 0.042, p = 0.045, and p = 0.006, respectively).
When we don't drink enough water, the body suffers. Good spinal health begins with good hydration. The spine is constructed in such a way that dehydration can cause limited mobility, decreased flexibility, and pain. It can cause the spine to age faster than it should which impacts the entire body.What can mimic a CSF leak? ›
POTS, orthostatic hypotension, cervicogenic headache, vestibular migraine, and prior Chiari decompression surgery are all causes of orthostatic headache that may mimic spinal CSF leak and must be distinguished for patients to receive appropriately directed therapy.What causes loss of spinal fluid? ›
What causes a cerebrospinal fluid leak? Some CSF leaks occur spontaneously and the cause is unknown, while others are a result of trauma such as a head injury, brain or spinal surgery, an epidural, a lumbar puncture (spinal tap) or a skull base tumor.What disorders are related to CSF? ›
CSF leaks, hydrocephalus, Chiari malformation and Syringomyelia fall under the umbrella of CSF disorders. This happens when the cerebrospinal fluid (CSF) builds up, putting pressure on the brain and leading to damage.How do you restore cerebrospinal fluid? ›
Surgery is a common method to repair CSF leaks. The surgery can either directly close a leak or help reconstruct a damaged area when the leak is from a significant injury. Some surgeries may go through your skull to access a leak, while others might try to repair a leak through your nose or mouth.What are the markers for MS on a spinal tap? ›
Spinal tap and MS diagnosis
Results indicating MS may include: Presence of oligoclonal bands, a group of proteins (called immunoglobulins) that show inflammation in the central nervous system. High levels of immunoglobulin G (IgG) antibodies. People with low levels of IgG are more prone to infections.
Magnetic resonance imaging (MRI) accurately detects CSF leaks and associated complications such as the encephaloceles and meningoceles.Can CSF leak be missed on MRI? ›
It is important to note that imaging of patients with spinal CSF leaks may sometimes be normal, and an MRI is not solely adequate in diagnosing a spinal CSF leak. Spinal CSF leaks can exist without any evidence of a leak on imaging. A negative MRI of the brain or spine does not rule out a spinal CSF leak.What if CSF test is positive? ›
In general, your CSF analysis results may show that you have an infection, an autoimmune disorder, such as multiple sclerosis (MS), or another disease or injury of the brain or spinal cord. Your provider will likely order more tests to confirm your diagnosis.Does MS show up in spinal fluid? ›
In MS, damage to myelin causes certain types of proteins to be released into the spinal fluid. When these proteins are identified in the spinal fluid, but not in the blood, MS is thought to be one of the possible diagnoses. Spinal fluid is obtained through a lumbar puncture (also known as a spinal tap).
These include fibromyalgia and vitamin B12 deficiency, muscular dystrophy (MD), amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), migraine, hypo-thyroidism, hypertension, Beçhets, Arnold-Chiari deformity, and mitochondrial disorders, although your neurologist can usually rule them out quite easily.What lab results indicate multiple sclerosis? ›
There are no specific tests for MS . Instead, a diagnosis of multiple sclerosis often relies on ruling out other conditions that might produce similar signs and symptoms, known as a differential diagnosis. Your doctor is likely to start with a thorough medical history and examination.How accurate is a spinal tap in diagnosing MS? ›
Also, these signs can show up in a number of other diseases, too. So a spinal tap by itself can't confirm or rule out a diagnosis of multiple sclerosis.Can you have MS lesions on spinal cord and not brain? ›
If a patient does have lesions in the spinal cord, he/she may be said to have Spinal MS. A smaller number of MS patients, approximately 20 percent, may have only spinal lesions and not brain lesions. I am an example of one of those 20 percent of MS patients who only have spinal lesions.Is a lumbar puncture better than an MRI for MS? ›
Often, the more convenient MRI scans is performed instead of the lumbar puncture. While MRI has become the most commonly used surrogate marker for MS, it is neither 100 percent sensitive nor 100 percent specific. The lumbar puncture remains a simple examination that yields valuable information.How to interpret CSF analysis? ›
- Appearance: Clear.
- Opening pressure: 10-20 cmCSF.
- WBC count: 0-5 cells/µL. < 2 polymorphonucleocytes [PMN]) ...
- Glucose level: >60% of serum glucose.
- Protein level: < 45 mg/dL.
- Consider additional tests: CSF culture, others depending on clinical findings.
Normally, there are no RBCs in the cerebrospinal fluid, and there should be no more than five WBCs per cubic millimeter of CSF. If your fluid contains RBCs, this may indicate bleeding. It is also possible that you had a traumatic tap (blood leaked into the fluid sample during collection).How much CSF is needed for flow cytometry? ›
Collect a minimum of 3 mL of CSF. If flow cytometry for lymphoma/leukemia is required, provide as much specimen as possible (CSF for flow cytometry must be submitted fresh).
In general, 0.5 to 1 mL of CSF is adequate for routine diagnostic tests, including cell counts, protein concentration, and cytological analysis. Larger volumes are necessary for additional diagnostics (cultures, titers, polymerase chain reaction [PCR], flow cytometry, protein electrophoresis, etc.).What is the minimum volume of CSF for culture? ›
Ideally a minimum volume of 1mL is required for microscopy and culture.
Cell Concentration/Cell number:
For each sample, you will need between 10^5 and 10^6 cells. If you are new to flow cytometry, use the higher number of cells -- to give yourself a margin for error (you always lose more cells than you expect during the staining and washing procedures).
The recommended cell concentration is 1 x 106/ sample, but 5 x 105/sample is the minimum required. Cells should be suspended in a volume of 0.25 ml – 1.0 ml. In case of live cells a viability dye should be used to exclude dead cells with higher autofluorescence from the analysis.What is the minimum size for flow cytometry? ›
In the flow cytometer, particles are carried to the laser intercept in a fluid stream. Any suspended particle or cell from 0.2–150 micrometers in size is suitable for analysis.What is the normal range for CSF routine examination? ›
|Cell count||0–5 lymphocytes/mcL|
|Glucose||40–80 mg/dL (< 40% of simultaneously measured plasma level if that plasma level is abnormal)|
|Myelin basic protein||< 1.5 ng/mL|
|Protein, total||15–60 mg/dL|
Cerebrospinal fluid (CSF) has essential biochemical and mechanical functions. CSF is produced at a rate of around 500 ml/day; there are estimates that there is approximately 125 mL to 150 mL of CSF in the body at any given time.Is cerebrospinal fluid cytology negative for malignancy? ›
As with most cytologic specimens, CSF cytology results are commonly reported as either “negative for malignancy,” “atypical,” “suspicious,” or “positive.” Over 90% of CSF specimens are assigned a cytologic diagnosis of “negative for malignant cells.”17 Many show only a small number of lymphocytes and monocytes, ...What is a normal CSF culture? ›
A normal result means no bacteria, viruses, or fungi grew in the laboratory dish. This is called a negative result. However, a normal result doesn't mean that an infection is present. The spinal tap and CSF smear may need to be done again.
In bacterial meningitis, the CSF glucose level (reference range, 40-70 mg/dL) is less than 40 mg/dL in 60% of patients. A simultaneous blood glucose determination should be obtained for the purposes of comparison.What does CSF culture no growth mean? ›
If there is no growth, the test is considered normal, or negative. The test is considered positive if bacteria, viruses, or fungi are detected in your CSF. This means there is an infection.How long does it take for spinal fluid to regenerate after a spinal tap? ›
The CSF is continually produced, and all of it is replaced every six to eight hours.
Radiological studies have shown that this clinical landmark is accurate in over 95% of the population,10 although in females or obese people Tuffier's Line tends to be found at a higher level than L4.What is the best level for lumbar puncture? ›
The desired insertion point of the needle is the L3-L4 or L4-L5 interspace; thus, the needle is inserted below the level of the spinal cord. The spinous process of L4 lies along an imaginary line between the top of the posterior superior iliac crests.