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CEREBROSPINAL FLUID Olar, Majalene DC.Bsmt3-1CEREBROSPINAL FLUIDCSF is the only fluid that exists in quantities sufficient to sample in healthy individuals.Present in volumes of 100 to 150 ml in adults; 60 to 100 ml in children; and 10 to 60 ml in newborns.This fluid bathes the brain and spinal column and serves as a cushion to protect the brain, as a circulating nutrient medium, as an excretory channel for nervous tissue metabolism, and as lubrication for the central nervous system.GROSS EXAMINATIONNormal CSF is clear, nonviscous, and colorless.A cloudy or hazy appearance may indicate the presence of WBCs ( greater than 200/mm3, RBCs (greater than 400/mm3), or microorganisms.Bloody fluid may be caused by a traumatic tap, in which blood is acquired as the puncture is performed or by a pathologic hemorrhage within the central nervous system.

GROSS EXAMINATIONIf more than 1 tube is received, the tubes can be observed for clearing from tube to tube.If the first tube contains blood but the remaining tubes are clear of progressively clearer, the blood is the result of a traumatic puncture.If all tubes are uniformly bloody, the probable cause is a subarachnoid hemorrhage.

GROSS EXAMINATIONWhen a bloody sample is received, an aliquot should be centrifuged, and the color if the supernatant should be observed and reported.A clear, colorless supernatant indicates a traumatic tap, whereas a yellowish or pinkish yellow tinge may indicate a subarachnoid hemorrhage. Yellowish color sometimes is referred as xanthochromia, but not all xanthochromia is pathologic. GROSS EXAMINATIONCLSI recommends simply reporting the actual color of the supernatant.Traumatic tapPathologic hemorrhageClear supernatantColored or hemolyzed supernatantClearing from tube to tubeSame appearance in all tubesBone marrow contaminationErythrophagesCartilage cellsSliderophages( may have bilirubin crystals)CELL COUNTS(contn)A CSF cell count is a test to measure the number of red and white blood cells that are in cerebrospinal fluid (CSF).When multiple tubes of spinal fluid are collected, the cell count is generally performed on tube 3, or the tube with the lowest possibility of peripheral blood contamination.Normal cell counts in CSF are 0-5 WBCs/mm3 and 0 RBCs/mm3.

CELL COUNTS(contn)CELL COUNTS (contn)CELL COUNTS (contn)A high WBC count may be found in fluid from patients with infective processes, such as meningitis.In general, WBC counts are much higher( in thousands) in patients with viral meningitis( in the hundreds).The predominant cell type present on the cytocentrifuge slide (neutrophils or lymphocytes), but a better indicator of the type of meningitis-bacterial or viral. Elevated WBC or nucleated cell counts also may be obtained in patients with inflammatory processes and malignancies.