Glutamine is a substance synthesized in the muscles, heart, and brain from ammonia and glutamic acid. It is found in the blood,skeletal muscles, and in cerebrospinal fluid. It is one of a few amino acids that cross the blood-brain barrier into the cerebrospinal fluid (CSF). Glutamine protects the central nervous system from toxic ammonia levels and is an indirect test for the detection of excess ammonia levels in the CSF. When ammonia is increased in the CSF, there is a lack of glutamic acid; therefore glutamine cannot be produced to remove the excess ammonia. This leads to coma. Glutamine is usually ordered on patients who are in a coma with no apparent cause. Elevated CSF glutamine is seen in hepatic encephalopathy, and levels can correlate with the severity of the disease. Elevated levels are also seen in liver disease (cirrhosis), severe meningitis, cerebral hemorrhage, and in Reye’s syndrome (an acute encephalopathy in children that is linked to a viral infection with influenza or varicella combined with aspirin use). Less commonly, glutamine levels are increased in aminoacidopathies such as arginase deficiency and citrullinemia, disorders usually diagnosed in infants and children that have delayed development or failure to thrive.
Cerebrospinal fluid glutamine tests are performed on cerebrospinal fluid (CSF) drawn from a patient from a spinal tap (lumbar puncture). In this procedure a long thin needle is inserted between the lumbar vertebrae L3/L4 or L4/L5 in the patient’s back and CSF is then collected. Additional tests may include Plasma Ammonia, Liver Function profile, and amino acid profile.
Reference ranges and specimen collection vary from test method and laboratories performing this test. To properly evaluate your test results, consult with the ordering physician or healthcare provider. If you would like to learn more about testing for Cerebrospinal Fluid Glutamine click here for further information or you can research one of the references listed below.
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