Examination 17721 CSF pack (CSF glucose, CSF protein, Xanthochromia) Purpose of test Cerebrospinal fluid (CSF) analysis may be used to help diagnose a wide variety of diseases and conditions affecting the central nervous system (CNS). Cell counts, protein, glucose, cell culture and Xanthochromia are the most frequently requested tests in CSF. These parameters are helpful in the diagnosis of subarachnoid haemorrhage, CNS infection and inflammatory conditions Measurement of CSF total protein, albumin, IgG, IgG Ratio, IgG Index and detection of oligoclonal bands in the CSF are useful as an aid to the diagnosis of multiple sclerosis Sample CSF and blood Sample Tube/Container For guidance on CSF tests and samples required a CSF Pack (containing tubes, forms and instruction sheet) is available from the biochemistry laboratory Sample Volume See instruction sheet in pack Special Precautions Follow the pack protocol. Sample for Xanthochromia must be collected > 12 hours after onset of symptoms Request Form: As per pack Laboratory Biochemistry Biological reference range Adults CSF glucose 2.22-3.89 mmol/L Children 3.33 -4.44 mmol/L CSF glucose values should be approximately 60 % of the plasma Adult CSF Protein 0.15 - 0.45 g/L Neonate CSF Protein 0.2-1.7gL Specific xanthochromia interpretative comment quoted see: Revised national guidelines for analysis of cerebrospinal fluid for bilirubin in suspected subarachnoid hemorrhage Ann Clin Biochem May 2008 45: 238-244 Clinical decision values Where the CSF WCC is elevated consideration should be given to the possibility of infection Where there is concern regarding meningoencephalitis PCR can be performed for common bacterial and viral causes of CNS infection. This is done in the Regional Virus Laboratory and can be arranged through the Mircobiology Laboratory Note: Printed documents are not controlled Page 1 of 3 Protein levels >1g/L often seen in Guillain Barre syndrome ACBI fluid guidelines 2009 Factors affecting performance CSF protein is elevated by 0.01g for every 1000RBCs/µL from SAH or traumatic tap CSF glucose ratio has limited utility in neonates and patients with hyperglycaemia Xanthochromia can be elevated when CSF protein >1.0g/L,serum bilirubin is >20µmol/L, repeat lumbar puncture, and traumatic tap Exposure to light causes a decay in bilirubin of 0.005AU/hour Xanthochromia can be reliably detected up to 2 week after onset of symptoms, negative results should be treated with caution if > 2 week post event High levels of Oxyhaemoglobin will obscure the bilirubin peak; Oxyhaemoglobin can be minimised by use of later samples and not transporting via pneumatic tube The performance of CSF scans for xanthochromia is highly dependent on the quality of the sample and the application in the correct clinical context. In a recent study it was reported that of 27 patients with scans consistent with SAH, only 11 had confirmed SAH. The false positives were due to traumatic tap (7) malignancy (1), infection (5) and unknown (3) Patient CSF samples containing >8 g/l of organically bound iodine from Radiopaque media (e.g. Hexabrix) may have falsely elevated protein results Turnaround times: Patient preparation See pack protocol Instructions for patient Not applicable collected sample Sample transportation Samples should not be transported using pneumatic air tube Special handling needs Samples for biochemistry must be protected from light by placing in a brown envelope Patient consent required Implied consent Specific rejection criteria Generic rejection applies Additional information NB. Plasma glucose and serum protein must be measured at the same time Note: Printed documents are not controlled Page 2 of 3 See CSF pack instructions Stability: unstable, must be transported to laboratory immediately. Minimum Retest Intervals- None available References Lab Tests Online WHO use of anticoagulants in diagnostic laboratory investigations ACBI fluid guidelines 2009 Cruickshank et al. Revised national guidelines for analysis of CSF for bilirubin in suspected SAH. Ann Clin Biochem 2008; 45: 238-244 Specificity of elevated cerebrospinal fluid bilirubin in the investigation of subarachnoid haemorrhage Ann Clin Biochem May 2015 52: 404-406 Note: Printed documents are not controlled Page 3 of 3.