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Cerebrospinal fluid is a clear fluid that surrounds the brain and provides the organ with protection and support. The fluid is produced and secreted by cells in the brain called ependymal cells. Certain infections and diseases can be diagnosed by testing samples of cerebrospinal fluid.
The fluid is produced in a central section of the brain called the choroid plexus. More than half of the choroid plexus is made up of ependymal cells, arranged in many layers of cells and blood vessels. The cells produce and secrete cerebrospinal fluid, and the fluid flows from the choroid plexus to circulate around the brain and spinal cord.
Cerebrospinal fluid has several functions. First, the fluid provides the brain with buoyancy, which allows the organ to support its own weight without collapsing. Without the fluid, the weight of the brain would prevent it from maintaining a constant blood supply to lower sections. The fluid also provides an important level of protection by acting as a mechanical buffer which prevents the brain and skull from coming into contact. Spinal fluid also helps remove metabolic waste from the brain and spinal cord. The fluid is constantly circulating around the brain and spinal cord, allowing waste to diffuse through the blood-brain barrier and be removed from the body.
Cerebrospinal fluid analysis is carried out to test the fluid for infection and other signs of disease. Healthy fluid is clear, but when bacterial infection is present, the fluid is cloudy and might contain blood. The types of proteins present or absent in the fluid also can provide diagnostic clues. Conditions that might require a spinal fluid analysis include encephalitis, epilepsy, hydrocephalus, meningitis and pituitary tumors.
The most common method for collecting the fluid is via a procedure called a lumbar puncture or spinal tap. The patient lies on his or her side with knees tucked toward the chest or sitting up in a bent-over position. The lower back is cleaned, and an anesthetic is injected into the spine. A fluid collection needle is then inserted into the lower back to collect a sample. After the sample is taken, the site is cleaned again and bandaged.
During this procedure, it is very important that the patient remain still while the fluid is being collected. This is because movement might cause the needle to move and injure the spinal cord. Careful cleaning of the area is important to prevent infection. In addition, the patient should rest for several hours following the procedure, in order to prevent any leakage of spinal fluid.
@ddljohn-- My sister had this done. It took her six weeks to get the results. The equipment needed to test spinal fluid isn't available at every lab, so don't be surprised if it takes a long time.
What they look for in the cerebrospinal fluid for diagnosis of autoimmune disorders, is antibodies. The same is true when there is an infection. When the body is fighting off infections, or fighting its own tissues due to an immune system disorder, it releases antibodies in the cerebrospinal fluid. They might look for some other substances as well, but I'm not sure what all of them are.
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