A great variety of neurological diseases require investigation of cerebrospinal fluid (CSF) to prove the diagnosis or to rule out relevant differential diagnoses. The objectives were to evaluate the theoretical background and provide guidelines for clinical use in routine CSF analysis including total
protein,
albumin,
immunoglobulins,
glucose,
lactate, cell count, cytological staining, and investigation of infectious CSF. The methods included a Systematic Medline search for the above-mentioned variables and review of appropriate publications by one or more of the task force members. Grading of evidence and recommendations was based on consensus by all task force members. It is recommended that CSF should be analysed immediately after collection. If storage is needed 12 ml of CSF should be partitioned into three to four sterile tubes.
Albumin CSF/serum ratio (Qalb) should be preferred to total
protein measurement and normal upper limits should be related to patients' age. Elevated Qalb is a non-specific finding but occurs mainly in bacterial, cryptococcal, and
tuberculous meningitis, leptomingeal
metastases as well as acute and chronic demyelinating
polyneuropathies. Pathological decrease of the CSF/serum
glucose ratio or increased
lactate concentration indicates bacterial or
fungal meningitis or leptomeningeal
metastases. Intrathecal
immunoglobulin G synthesis is best demonstrated by isoelectric focusing followed by specific staining. Cellular morphology (cytological staining) should be evaluated whenever
pleocytosis is found or leptomeningeal
metastases or pathological
bleeding is suspected. Computed tomography-negative intrathecal
bleeding should be investigated by
bilirubin detection.