Bilirubin in CSF
It is crucially important to detect subarachnoid haemorrhage ( SAH ) in all patients in whom it has occurred to select patients for angiography and preventative surgery. A computerized tomography ( CT ) scan is positive in up to 98% of patients with SAH presenting within 12 hours, but is positive in only 50% of those presenting within one week.
Cerebrospinal fluid ( CSF ) bilirubin spectrophotometry can be used to determine the need for angiography in those few CT-negative patients in whom clinical suspicion of a SAH remains high; it may remain positive up to two weeks after the event. A lumbar puncture (LP) should only be performed > 12 hours after the onset of presenting symptoms. Whenever possible collect sequential specimens. Always ensure that the least blood-stained CSF sample taken (usually the last) is sent for bilirubin analysis. Protect the CSF from light and avoid vacuum tube transport systems, if possible. Always use spectrophotometry in preference to visual inspection. All CSF specimens are precious and should always be analysed unless an insufficient sample is received. Centrifuge the specimen at >2000rpm for 5 min as soon as possible after receipt in the laboratory. Store the supernatant at 4oC in the dark until analysis. An increase in CSF bilirubin is the key finding, which supports the occurrence of SAH but is not specific for this. In most positive cases, bilirubin will occur with oxyhaemoglobin.
Ann Clin Biochem 2008; 45: 238-244. DOI: 10.1258/acb.2008.007257
UV/Vis spectrophotometry scans of CSF xanthochromia although the recommended technique can be difficult to interpret. The trace produced requires the user to manually draw a tangent between two points. This in many cases can be very subjective and offers the potential for introducing calculation errors.
NorthStar Scientific offer the BIO-C system for the analysis of bilirubin xanthochromia in CSF. This comprises a BIO-UV double beam UV/Vis spectrophotometer together with fully automatic data analysis software. The BIO-C software follows the Revised National Guidelines for analysis of CSF for bilirubin in suspected SAH. Calculations are performed and a report is produced.
NEW – Bio-C Version 8 software in combination with our BIO-UV spectrophotometer offers the biochemistry laboratory a simple, assured means of measuring bilirubin xanthochromia in CSF
Key features of BIO-C V8 include:
- Automatic Baseline as standard with manual mode. The manual mode can be selected by the user and upper and lower wavelength position selected.
- Calculation of bilirubin value at 476nm with oxyhaemoglobin peak (position and value).
- Correction to bilirubin value can be made by inputting the Serum bilirubin, CSF protein and Serum total protein values.
- Revised National Guidelines appropriate message displayed together with user configurable message.
- Oxyhaemoglobin value determined. If value is less than 0.02 Abs. The appropriate negative message is displayed. This is as requested by NEQAS
- Barcode image displayed on printout and screen.
- Result signoff and data encryption for added security.
- Software updates supplied free of charge during the 12 months warranty period.
- User editable text inputs for patient name Lab no., comments etc. These are all stored with the data.
- Full printout is produced detailing all the results.
- Time of sampling to onset of symptoms is recorded.