Cerebrospinal fluid (CSF) analysis


Cerebrospinal fluid (CSF) analysis is a set of laboratory tests that examine a sample of the fluid surrounding the brain and spinal cord. This fluid is an ultrafiltrate of plasma. It is clear and colorless. It contains glucose, electrolytes, amino acids, and other small molecules found in plasma, but has very little protein and few cells. CSF protects the central nervous system from injury, cushions it from the surrounding bone structure, provides it with nutrients, and removes waste products by returning them to the blood. CSF is withdrawn from the subarachnoid space through a needle by a procedure called a lumbar puncture or spinal tap. CSF analysis includes tests in clinical chemistry, hematology, immunology, and microbiology. Usually three or four tubes are collected. The first tube is used for chemical and/or serological analysis and the last two tubes are used for hematology and microbiology tests. This reduces the chances of a falsely elevated white cell count caused by a traumatic tap (bleeding into the subarachnoid space at the puncture site), and contamination of the bacterial culture by skin germs or flora.


The purpose of a CSF analysis is to diagnose medical disorders that affect the central nervous system. Some of these conditions are:

Routine examination of CSF includes visual observation of color and clarity and tests for glucose, protein, lactate, lactate dehydrogenase, red blood cell count, white blood cell count with differential, syphilis serology (testing for antibodies indicative of syphilis), Gram stain, and bacterial culture. Further tests may need to be performed depending upon the results of initial tests and the presumptive diagnosis. For example, an abnormally high total protein seen in a patient suspected of having a demyelinating disease such as multiple sclerosis dictates CSF protein electrophoresis and measurement of immunoglobulin levels and myelin basic protein.

GROSS EXAMINATION. Color and clarity are important diagnostic characteristics of CSF. Straw, pink, yellow, or amber pigments (xanthochromia) are abnormal and indicate the presence of bilirubin, hemoglobin, red blood cells, or increased protein. Turbidity (suspended particles) indicates an increased number of cells. Gross examination is an important aid to differentiating a subarachnoid hemorrhage from a traumatic tap. The latter is often associated with sequential clearing of CSF as it is collected; streaks of blood in an otherwise clear fluid; or a sample that clots.

GLUCOSE. CSF glucose is normally approximately two-thirds of the fasting plasma glucose. A glucose level below 40 mg/dL is significant and occurs in bacterial and fungal meningitis and in malignancy.

PROTEIN. Total protein levels in CSF are normally very low, and albumin makes up approximately twothirds of the total. High levels are seen in many conditions including bacterial and fungal meningitis, multiple sclerosis, tumors, subarachnoid hemorrhage, and traumatic tap.

LACTATE. The CSF lactate is used mainly to help differentiate bacterial and fungal meningitis, which cause increased lactate, from viral meningitis, which does not.

LACTATE DEHYDROGENASE. This enzyme is elevated in bacterial and fungal meningitis, malignancy, and subarachnoid hemorrhage.

WHITE BLOOD CELL (WBC) COUNT. The number of white blood cells in CSF is very low, usually necessitating a manual WBC count. An increase in WBCs may occur in many conditions including infection (viral, bacterial, fungal, and parasitic), allergy, leukemia, multiple sclerosis, hemorrhage, traumatic tap, encephalitis, and Guillain-Barré syndrome. The WBC differential helps to distinguish many of these causes. For example, viral infection is usually associated with an increase in lymphocytes, while bacterial and fungal infections are associated with an increase in polymorphonuclear leukocytes (neutrophils). The differential may also reveal eosinophils associated with allergy and ventricular shunts; macrophages with ingested bacteria (indicating meningitis), RBCs (indicating hemorrhage), or lipids (indicating possible cerebral infarction); blasts (immature cells) that indicate leukemia; and malignant cells characteristic of the tissue of origin. About 50% of metastatic cancers that infiltrate the central nervous system and about 10% of central nervous system tumors will shed cells into the CSF.

RED BLOOD CELL (RBC) COUNT. While not normally found in CSF, RBCs will appear whenever bleeding has occurred. Red cells in CSF signal subarachnoid hemorrhage, stroke, or traumatic tap. Since white cells may enter the CSF in response to local infection, inflammation, or bleeding, the RBC count is used to correct the WBC count so that it reflects conditions other than hemorrhage or a traumatic tap. This is accomplished by counting RBCs and WBCs in both blood and CSF. The ratio of RBCs in CSF to blood is multiplied by the blood WBC count. This value is subtracted from the CSF WBC count to eliminate WBCs derived from hemorrhage or traumatic tap.

GRAM STAIN. The Gram stain is performed on a sediment of the CSF and is positive in at least 60% of cases of bacterial meningitis. Culture is performed for both aerobic and anaerobic bacteria. In addition, other stains (e.g. the acid-fast stain for Mycobacterium tuberculosis , fungal culture, and rapid identification tests [tests for bacterial and fungal antigens]) may be performed routinely.

SYPHILIS SEROLOGY. This involves testing for antibodies that indicate neurosyphilis. The fluorescent treponemal antibody-absorption (FTA-ABS) test is often used and is positive in persons with active and treated syphilis. The test is used in conjunction with the VDRL test for nontreponemal antibodies, which is positive in most persons with active syphilis, but negative in treated cases.


In some circumstances, a lumbar puncture to withdraw a small amount of CSF for analysis may lead to serious complications. Lumbar punctures should be performed only with extreme caution, and only if the benefits are thought to outweigh the risks. In people who have bleeding disorders, lumbar puncture can cause hemorrhage that can compress the spinal cord. If there is increased spinal column pressure, as may occur with a brain tumor and other conditions, removal of CSF can cause the brain to herniate, compressing the brain stem and other vital structures and leading to irreversible brain damage or death. Bacteria introduced during the puncture may cause meningitis. For this reason, aseptic technique must be followed strictly, and a lumbar puncture should never be performed at the site of a localized skin lesion.

Specimens should be handled with caution to avoid contamination with skin flora. They should be refrigerated if analysis cannot be performed immediately.


Lumbar puncture is performed by inserting the needle between the fourth and fifth lumbar vertabrae (L4-L5). This location is used because the spinal cord stops near L2, and a needle introduced below this level will miss the cord. In rare instances, such as a spinal fluid blockage in the middle of the back, a physician may perform a spinal tap in the cervical spine.


After the procedure, the site of the puncture is covered with a sterile bandage. The patient should remain lying down for four to six hours after the lumbar puncture. Vital signs should be monitored every 15 minutes for four hours, then every 30 minutes for another four hours. The puncture site should be observed for signs of weeping or swelling for 24 hours. The neurological status of the patient should also be evaluated for such symptoms as numbness and/or tingling in the lower extremities.


The most common side effect after the removal of CSF is a headache. This occurs in 10–30% of adult patients and in up to 40% of children. It is caused by a decreased CSF pressure related to a small leak of CSF through the puncture site. These headaches usually are a dull pain, although some people report a throbbing sensation. A stiff neck and nausea may accompany the headache. Lumbar puncture headaches typically begin within two days after the procedure and persist from a few days to several weeks or months.

Normal results



Braunwald, Eugene, et al., eds., "Approach to the Patient with Neurologic Disease." In Harrison's Principles of Internal Medicine. 15th ed. New York: McGraw-Hill, 2001.

Henry, J. B. Clinical Diagnosis and Management by Laboratory Methods. 20th ed. Philadelphia, PA: W. B. Saunders, 2001.

Kee, Joyce LeFever. Handbook of Laboratory and Diagnostic Tests. 4th ed. Upper Saddle River, NJ: Prentice Hall, 2001.

Smith, Gregory P., and Carl R. Kieldsberg. Cerebrospinal, Synovial, and Serous Body Fluids. Philadelphia, PA: W. B. Saunders, 2001.

Wallach, Jacques. Interpretation of Diagnostic Tests. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2000.


National Institutes of Health. March 14, 2003 [cited April 5, 2003]. http://www.nlm.nih.gov/medlineplus/encyclopedia.html .

Victoria E. DeMoranville Mark A. Best

User Contributions:

Its was great to read your topic, I just had a spinal tap with protein numbers reading 60, was trying to find lamens terms of what that really means or is? Thanks
Lisa Renee Bosworth
I,Lisa Bosworth gave a very completed,very good comment on you'r hard work to provide an artical such as this comment space is for.I also added important procedure percautions that are not always thaught to be important,per a patient.Thank You,LRB
Hi, l found this article really good in helping me understand why my neuro has narrowed down the search for my health issues(suspected MS)tests tests and more tests, good luck to all reading the article.Michelle
Your article helped me so much. I had a spinal tap done in the ER. I was having extreme head pain, nausea, stiff/aching neck, blurred vision, mild fainting, ect.. The ER did a Cat Scan also. My protein levels were 60. The ER doctor sent me home 1 hour after my spinal tap. She said since my protein levels were not over 100 that I could go home. After reading your article I now know this hospital should have kept me over night. They never did any blood work or tests after my spinal tap. Since that procedure I have had many more episodes of this extreme crippling head pain. But since then,I no longer have health insurance so I just have to stay in bed for hours, sometimes days, to deal with the pain. I wish I read your article before my nightmare in the ER. I would have insisted that the doctor keep me for the recommended 24 hrs. This happened 14 months ago and I still have this extreme head pain 1-4 times a month. I'm so mad, I want to track down that ER doctor and give her a piece of my anger. Thanks to your web site, I now have some answers. Since I can't go to a doctor(no health coverage) I look on here to find answers why I'm still having all the same symptoms I orginally went to the ER for. Thanks again for a great site :)
Cade Gullickson
I am a Medical Technologist with a Specialist Certification in Hematology. There is some debate right now in our system of hospital labs as to what significance or purpose there is to a physician ordering multiple cell counts on a collection--usually tube #1 and #3 or tube #2 and #4--on CSFs that are colorless and clear and in which the diagnosis or suspected diagnosis is not subarachnoid hemorrhage. My concern is that we are performing unnecessary testing and possibly violating HIPAA rules by doing these multiple cell counts in which, invariably, the information from the higher numbered tube is representative of the sample and the patient's condition.
Is there any references concerning these multiple cell counts when a traumatic tap or subarachnoid hemorrhage is not suspected and all tubes are colorless and clear?
Thank you

Cade Duel Gullickson, MT, SH (ASCP)
I had 3 mri showing t2 lessions worse each time, spinal tap showing 7 non matching bands protien level of 56 and NO DIAGNOSIS WHY
San-Mari Geldenhuys
I'm a Medical Technology student from South Africa, and would like to thank you for the great article !!! It's really informative and academic and helped me a great deal in my research . Thanks again
Jamal Al Adam
I am a Nurse, i am working in the NICU.
I need some information about CSF test results.
thanks alot
jamal adam
it is agood topicand satisfy.but there no comment and differency in pediatric. thanks
I'm a medical student in Mbarara university in Uganda,your article is so good that it has given me some information and precautions in diagnosis of various forms of meningitis.It will help me to take action during outbreaks of meningitis in Uganda especially during dry seasons.
stanley khoswe
the topic is very clear and easy to understand, it has helped me a lot. am a laboratory technician in Malawi
this data includes excellant and useful information.
I came across this article while searching for info on immature cells in CFS. My son, 18, has been treated for the last 2 years for leukemia. He had a spinal 3 weeks ago to administer methotrexate and biopsy. I noticed immediately that there was a pink tinge to the fluid, unlike all of the other LP's and the oncologist said it was no doubt a blood vessel. Now, I received a call from the oncologist informing me that there were immature cells found in the CSF. I learned that there, in fact, could be blood in the fluid or that it was a traumatic tap causing the pink fluid. Tubes 3 and 4 appeared clear. I am hoping that this repeated LP will disclose false results..thank you
I had a spinal tap done a couple of months ago and I had 3 red blood cells in my spinal fluid. Is this anything to worry about or is it just routine to have a few red blood cells in the fluid?
In CSF of my nephew total protine observed as 60.4 mg%
The problem started 3 months ago with double vision and gradually disturbance in limb alighment. Although now limb function is normal but still problem in vision.What may be the cause of excess protine? How can it be cured?Any complication in future , he is 16 yrs of age.

Santosh Pant
Hi, Im from Serbija and I work on clinical for neurology in laboratory. I want to now how am I diferential WBS and wich color to use when I diferencial polymorphonuclear from lymphocite. We use Fuchs-Rosenthal chamber and Gimsa color. What do you think is this all right?
am a medical laboratory technologist to be,and the article helped supplement what i was told in class however i was looking forward to see how a CSF specimen is processed
I felt that the information provided was very useful in the diagnosis and explaination of the CSF results. I have had an elevated ACE and my Nerologist can't really give me a good reason as to why. I have been diagnosed with MS and take Interferon Injections. What happens when your B/P is staying elevated and you are taking ACE Inhibitors? Will this interfer with the CSF results? I get headaches and the Radiologist that performed the CSF collection stated that the flow was very slow and took quite some time to collect. It did look somwhat amber in color???

Thank You
I had a RBC reading of 20 show up in my CSF report and the ref range is 0-0. Noone mentioned anything about it to me and I just happened to be reviewing the copy of my report today. Should I be concerned about this? Thanks for your help.
Hi I had a lumbar punture Thrusday with floroscopy and two doctors were unable to get my fluid they were in trust me i had bladder spasms legs had electric shocks and many more awful pains they tried for 1 hour then said that my pressure was to low! i need this spinal fluid because dr thanks i have ms. Have you heard of this thanks Barbara
Thanks for the article it was very informative. i just had a CSF done last night around midnite and i didnt experience any headaches but i did wake up with a minor ache in my lower back throughout the day. Should i be worried or is the minor ache a usual feeling aftr the procedure and will it go away?
great article and i thank for this, i made my presentation on CSF diagnostics from this one and most importantly references are mentioned which is a very good practice in making an article authentic. good job
information for dilution of csf for counting cells.
Could a iv of prednisone used to stabilize mast cells in an appendectomy
influence the results of a LP in regard to bacteria or fungus? Another Iv of prednisone would also have been given with the LP. Thank you. Great article.
too good n precise... i found this article very interesting n informative.. good work..
I had a lp done a yr ago. The result came out w/ 11 bands and a normal person has 10, so what does this mean? No one could tell me. Help please.
what happens if csf sugar level is 12 in newborn...
I had a lumbar Punch and my lymphs was 95 out of range and monocytes whild in range was 5 on the low range. I am not understanding what this means. Also WBC was 5.
The article is so explanatory. And as a Biochemist i say it is a job well - done.
Thanks for information. Its very easy to understand and clear.
thanks the topic was short and clear
i understand it easily
thanks for information. what happened if CSF sugar level below 10 mg
i need another information about
abnormal characteristics of CSF ??
i need another information about
abnormal characteristics of CSF ??
shailendra vashistha
Abai sunday
Am a laboratory technician from uganda, i realy thank you so much for this page you have show to us about csf analysis it help me so much in standising & improving on da procedure because i know the importance of the defferent tests and their normal ranges.
I see there have not been any answers since May. In May '10 I started having some leg weakness and feeling like I may faint...but it was more of a ride on the roller coaster, my stomach lost it as I was riding a ride but that quick went down. I do have high cholesterol with 3 stents in lower extremities. By Nov. 2011, I started having sciatica attacks in right leg. I had several attacks in a 4 month time limit. After each one my right leg became weaker and weaker until I was using a cane. Went to PT to strengthen legs, but my right leg swelled to back of calf. Tested for blood clot...negative...sent to an ortho doc and a cast was put on and all he could tell me I may have a bad splint, but I made him take off at 4 weeks, the swelling had left but every time I walked the front of shin hurt very bad. Cast taken off, a decubitus formed on top of shin bone, Being a nurse before being disabled, I had taken care of that.
I started going to a neurologist, because of weakness and spasms of right leg and back at night. Can not sleep..pain everywhere you touch in back. 3MRIs done on back...only arthritis increased, the cervical showed another mild bulging disc but did the brain MRI and showed ischemic places and plaque (lesions) but not inflamed per-say. The PA wanted to start me on high doses of prednisone and then wean me...so they can put a prognosis to this. But the neurologist did not want to do and decided on the lumbar puncture. What is he looking for. I was just shocked...because the last spinal lumbar puncture I assisted with was my father and he found out that day he had leukemia...the type that runs in families. My mother has Alzheimer's. Is there anyway you can tell me what my neurologist is looking for? Please can you tell me?
This article is very helpful in understanding the basic medical procedure. i appreciate it
I had a spinal tap last month & my red blood cells are 314. I still don't have the results as we were checking for neurosarcoidosis. I'm worried about the red blood cells though. Any thoughts?
Chanel Smith
Hi my name is Chanel and I'm a mother of four who's been having muscle weakness and pain in my arms and legs, and lung problems plus bowel trouble for over a year but recently I passed out twice and had pain on the left hide of my head. Then three months ago I started having bad pain and stiffness in my spine and I could feel a lump and my family too but my doctor said I'm very thin and this lump was part of my back. I'm also now 89Lbs 5ft4inches at 38 years old. I lost a lot of weight also I did weigh 115lbs almost two years ago. Well back in December the day after Christmas my husband had to call the ambulance cause the pain in my head and spine and neck had gotten to be unbearable. At the hospital they did a CT scan to rule out bleeding in the brain and a spinal lumber puncture. The CT was Neg and the spinal puncture show a protein level of 154. Can anyone tell me what this means my doctor said I had to see the neurologist cause she wasn't comfortable with these levels. Thank You Chanel!!
SALAM, I am a lab technologist, i found this article simple and easily understood, it is helpful for both patients and medical professionals.
Thanks.iam very saticfy to such object.but i hope more than such information about this .
May I know who should do the CSF Differntial & Cell Count??

Is it done by Hematology or Microbiology

Technician or Pathologist?
I had a lumbar pucture done to test for MS. Only things high were the protein was 75.4 (H) and there were 3 oligoclonal bands. Should I be concerned?
Right now i am in a lab seated for CSF analysis, i always think of reporting any lab results for proper diagnosis after i at least have had enough information to up date me on the current scientific work. Any way i liked much this article as a biomedical lab scientist.
Thanks.Iam lab Tech ifound this article is very simple and understand ,

i need another information about abnormal characteristics of newborn CSF ??
Great information.. i had went to the ER after 3 day of taking advil,tylonel and other pills for my headache but none seem to do effect..(all were tooking at appropriate timing)..Day 2 i was heavily sweating i couldn't tolerate noise or funky smells and had a stiff neck with a headache ranging (1-10) was a 6 with a discomfort in my back..almost fainted and was sent home from work but had real bad nausea..Day 3 i couldn't sleep the pain had worsen and decided to go to the hospital..i was only giving IV FLUIDS,morphine 4 and zofran 4 and was diagnosed with acute sinusitis and dehydration which i believe the cause of that i was constantly throwing up and was quickly discharged..i felt fine at first but when i was picked up and got in the car the pain came back..i jad the urge to throw up but i was thinking maybe with the medication i was giving it was calm down.i was taking them but the pain yet wouldn't go away.i couldn't go to work and had 4 days of sleepless nights and severe headaches..i only wanted to be in bed..day 4 i was tooking to ER Again.the pain was a 10 amd was crying softly of pain and irritated of little sleep..i was looked at again..a CT SCAN was performed but results were negative..i was injected with 10 mg of Decadron,10 mg of Reglan,2and ivp of Benadryl and 2 grams of Rocephin..over 30 minutes..after i gave them approval a lumbar puncture was performed and the Docter did use a clean kit..after all that my laboratory results came including CSF RESULTS DID SHOW WBC TUBE 4 AS ELEVATED TO 40 WHICH INDICATED A VIRAL MENINGitis..i was discharged the same day had the side affects of unable to stand,nausea,didn't tolerate light nor eat.my medication was PEROCET 7.5 FOR PAIN,IBUPROFEN 600 MG..I was like this for a month with pain and was constipated for a week due to the fact i didn't eat and drinked very little fluids and was constantly throwing up and when i stood up it felt like my head was about to pop since the pain would come back,i couldn't be in the car more then 5 minutes i was constantly sweating..medication was my only relif and i would only sleep..it was a horrible and traumatic eexperience..thought it was due to stress that is why i didn't react quick but the doctor told i made it in time before it grown bacteria but now i know i was suppose to be kept over night but was not..iwas
I loved the site and article but I am left with my original question. Is there any site or a single person that can answer the question I have been entering over and over? What could be the cause of an IgG index -2.8 (norm is 0-3.8) with a csf albumin of 26.1 (norm is 13.4-23.7) I have been unable to find any information when your results are on the low side. If you know of any site I could try I would deeply appreciate the help thank you
I've had a sore back and leg numbness for several years. Last year I had surgery to repair a bulging disc in my back. Before the surgery they did an MRI and saw a bundle of swollen and enflamed nerves in my lower back. They tried to do a spinal tap but was unable to get any fluid. The nerves were so swollen they couldn't get to the fluid. The first time they had me on my side and jabbed me over a dozen times, with no luck just a lot of pain. Two days later they tried again with the same results. I just had another attempt a few days ago. This time a different hospital and doctor. They used a special ex-ray machine and had me lay on my stomach. Two hours later and the same results. Could not get any fluid. Has anyone been through a similar situation? They told me the nerves at the end of the spine are basically in a bundle. The swelling hasn't change in a year. I'm at a loss and don't know what to do next. Any help would be greatly appreciated.
Does the lumbar puncture procedure cause an inflammatory response in neonates? In a practical I found a CSF WBC count of 90,000 mm3.
I had a spinal tap 3 weeks ago and te reported says rare degenerative lymphocytes, monocytes, and neutrophils I do not have any idea what this mean, Please I was searching information on internet but no result of this meaning, Thank you for your help
Myelin basic protein was at 1.6. What does that mean? I also had a high serum albumin. I have been experiencing numerous neurological symptoms with extreme muscle weakness and fatigue.
My CSF protein was 72 and tried to find out what the was through multiple emails and messages to my Neurologist as well as contact with facility where labs taken. No one responded from M.D. office and Lab referred me to M.D. Seven days later I got a call from Lab that I had to come in and do blood work for MS profile THAT day or it would be too late to correlate to CSF. My understanding is the protein breakdown must be done on Spinal Fluid taken. Am I wrong or will another Tap be needed for differential indicated DX
Vanessa Giles
Very informative article. I'm particularly interested in the reasons for abnormal colourings - the article states that these "indicate the presence of bilirubin, hemoglobin, red blood cells", etc. Could yellow CSF also be found as a result of what could be termed a previous or old injury?
I’ve been experiencing a feeling in my head that feels like somebody loaded me up with any histamines I feel fuzzy I feel groggy I feel confused and I have pressure headaches. In 1995 on March 14 I had a cerebral aneurysm rupture on July 7, 1995 I had an aneurysm on the other side of my head clamped and in September 2015 I had a bypass done on an aneurysm. I’ve been to the emergency room twice they did a CAT scan the first time but what night do you and MRI until I showed them a letter that my first brackets from the ruptured aneurysm in 1995 was MRI safe. I went back in with extreme head pressure a feeling that my jaw was locked and again confusion as if somebody drugged me. They did a spinal tap and the only results I came back with was the doctor saying I only had two white blood cells. I don’t know what this means and I’m not finding any answers for my debilitating problem. It is kept me off work, unable to drive, and I sleep most the time. Do you have any ideas on what I Should do next? The emergency room told me to not come back

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