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How long do lumbar puncture results take?


A lumbar puncture (LP) can also be referred to as a “Spinal Tap”, “Lumbar Tap” “Lumbal Punction” and “Lumbar Punch” which is a medical procedure conducted for diagnosis or to proffer solution of a condition. 

This diagnosis can include brutal infection such as the Guillain-Barre syndrome, meningitis, multiple sclerosis, cancers of the brain or spinal cord. 

Although, the lumbar puncture can also be used to inject chemotherapy drugs or anesthetic medications into the cerebrospinal fluid. 

The lumbar puncture is mainly performed in the lower back where the lumbar region is located by obtaining a fluid sample known as the “Cerebrospinal Fluid (CSF)”. 

This cerebrospinal fluid is a clear fluid that bathes and surrounds the brain and the spinal cord which is responsible for the protection of these body parts from injury. The cerebrospinal fluid is frequently made and constantly reabsorbed in the brain with varying compositions of water, proteins, sugars, cells and another type of substances which are present to regulate and maintain the balance in the central nervous system. 

This fluid is obtained by insertion of a hollow needle into space in the lumbar region between the two lumbar vertebrae known as the subarachnoid space to extract the sample.


A lumbar puncture can be done for different reasons, though, the most common reason for performing the spinal tap is to remove a small sample of cerebrospinal fluid for laboratory testing as it can aid the diagnosis of several disorders, they can measure the pressure rate in the cerebrospinal fluid.

They can also be used for the injection of dye or radioactive substances chemotherapy drugs, anesthetics, and other forms of medications relating to the nervous system. 

Major disorders which are diagnosed with the aid of the lumbar puncture are:

  • Encephalitis

This condition is a result of the inflammation of the brain which is mainly caused by a virus. 

  • Meningitis Lumbar Puncture

This is known as the inflammation of the membrane surrounding the spinal cord and brain mainly caused by a virus, fungal or bacterial infection. 

  • Reye Syndrome

This is a very fatal disease that results in severe conditions that could damage the brain or organs. The cause of this syndrome is not known though the lumbar puncture in children can be a result of aspirin administered to them. 

Therefore, it is not advisable to administer aspirin to children when they are diagnosed with any form of sickness except a medical professional recommends it.

  • Bleeding

Bleeding tends to occur in the subarachnoid space between the tissues surrounding the brain and the brain itself.

  • Lumbar Puncture Headache

A spinal tap can be done to diagnose some inflammatory conditions which may result in a headache.

  • Myelitis

This condition is caused by the inflammation of the bone tissues in the bone marrow or the spinal cord.

  • Guillain-Barre Syndrome

This syndrome is a disorder where the immune system in the body attacks some part of the nervous system.

  • Normal Pressure Hydrocephalus

This is a rare condition that affects majorly old people in which there is a loss in the control of urination, memory loss issue, and an unstable gait.

  • Neurosyphilis

This is a phase in syphilis where the bacteria invades the central nervous system.

  • Demyelinating Diseases

These diseases are responsible for the attack on the protective coating in parts of the nerve fibers. Examples of these diseases are acute demyelination or multiple sclerosis.

  • Pseudotumor Cerebri

This condition is also referred to as idiopathic intracranial hypertension and involves elevated pressure in the subarachnoid space which occurs without a cause. This lumbar puncture is done after head imaging has been done.


Lumbar Puncture side effects are rare as the process is safe but as usual, there must be adverse effects which are listed below:

  1. Post-lumbar puncture headache.  
  2. Back discomfort or pain. 
  3. Bleeding. 
  4. Brainstem herniation. 


Preparing for the process involves the doctor enquiring for the patient’s medical history, performing a physical exam, and blood tests for any disorder.

Some foods, drinks, and medication limitations will be specified by the doctor such as blood-thinning or anticoagulants like warfarin, clopidogrel, aspirin. Lumbar puncture is performed in an outpatient facility mainly a hospital by a doctor.


The procedure is grouped into the activities before, during, and after the procedure. This procedure is listed below:

  • Before the Procedure:

Changing to a hospital gown may be required of the patient before laying on the side with the knees drawn to the chest or seat and lean forward on a stable surface. Therefore, any position that can lead to widening the spaces between the two vertebrae in the lumbar region for easy extraction of the cerebrospinal fluid can be utilized.

For children, the guardian will need to hold the child in position while the procedure is ongoing. Then, the back is washed with an antiseptic soap or iodine.

  • During the Procedure:

In this case, local anesthesia is injected into the lower back of the patient to make the region numb for puncturing, though it might sting a bit. 

Afterward, a hollow but thin needle is inserted in the lumbar region between the two lower vertebrae, through the dura which is the spinal membrane, then into the spinal canal. 

After the needle has been inserted, the patient may be asked to slightly change the positioning of the body and the pressure of the cerebrospinal fluid is measured and a little amount is withdrawn before the pressure is measured before it is finally removed and the region punctured in the lower back is covered with a bandage. Then the patient lays down for a while after the procedure. The procedure can take about 45 minutes to perform.

In some cases, ultrasound is used for children and infants to aid the prevention of deep insertion into the child. This ultrasound guides the insertion during the procedure. 

  • After the Procedure:

Basically, after the procedure, the patient is to rest, restrict participation in strenuous activities on that day of the procedure. 

The patient may return to work if the job does not involve physicality or physical action. The activities of the patient are to be discussed with the doctor for proper counseling on things to do and what not to do.    

Taking a pain-relieving medication with the contents of acetaminophen can aid the reduction of side effects like headache and back pain.


The cerebrospinal fluid samples will be taken to the laboratory for proper analysis. Factors that are looked out for when examining the spinal fluid are:

  • White Blood Cells

The cerebrospinal fluid normally possesses up to five white blood cells per microliter, therefore an increase in the number of white blood cells present indicates a possible infection.

  • Protein

Protein level above 45 milligrams per deciliter (mg/dL) at an elevated level in the cerebrospinal fluid indicates an inflammatory or an infection in the body.

  • Sugar

A low level of glucose in the spinal fluid indicates a possible infection or another condition.

  • Cancer Cells

The presence of some abnormal cells in the cerebrospinal fluid such as an immature blood cell or a tumor predicts a presence of cancer in the body.

  • General Appearance

Generally, the cerebrospinal fluid is colorless and clear, therefore, any cloudy, yellow, or pink-colored fluid shows abnormal bleeding but if the fluid is green it can be deduced that there is the presence of bilirubin or an infection.

  • Microorganisms

Bacteria, fungi, viruses, or other forms of microorganisms present in the spinal fluid may indicate an infection.


The cost of a lumbar puncture in US Dollars ranges between $800 to $1500.


  • Can you become paralyzed from a lumbar puncture?

Due to the position of insertion at the lower back, there is just a very slight chance of damaging the nerve or becoming paralyzed.


  • How long do lumbar puncture results take?

Some parts of the result might be related to the patient at first but it takes about 48 hours for full results to be available.


  • What diseases can be found in the spinal fluid?

Conditions like an autoimmune disorder, infectious disease of the brain, bleeding in the brain, and brain tumors can be found in the spinal fluid.


  • How many lumbar punctures can a person have?

The patients are not allowed to receive insertion of the needle more than 3 times a day because it can lead to an incorrect reading.  


  • How long are you sore after a spinal tap?

Close monitoring of any changes in health is mandatory as any noticeable form of change without consultation with the doctor is bad.