Revised national guidelines for analysis of CSF for bilirubin in suspected SAH

This version was published on 1 November 2008

Ann Clin Biochem 2008;45:617-618
doi:10.1258/acb.2008.081101
© 2008 Association for Clinical Biochemistry

 

This Article
Right arrow

Full Text (PDF)

Right arrow
All Versions of this Article:

acb.2008.081101v1

45/6/617

most recent

Right arrow
Alert me when this article is cited
Right arrow
Alert me if a correction is posted
Services
Right arrow
Email this article to a friend
Right arrow

Similar articles in this journal

Right arrow
Similar articles in PubMed
Right arrow
Alert me to new issues of the journal
Right arrow
Download to citation manager
Right arrow
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow
Articles by Florkowski, C M
Right arrow
Articles by George, P M
Right arrow Search for Related Content
PubMed
Right arrow
PubMed Citation
Social Bookmarking

What’s this?

Letters


We are pleased to see the evolution of the UK guidelines in this area (Ann Clin Biochem 2008;45:238–244), although contest the view that analysis of bilirubin in CSF using diazo methods has not been adequately validated in this context and should not be used.1 We developed such an approach to diagnosis,2,3 now used routinely in our laboratory to identify approximately 90% of samples that do not need to be submitted to spectrophotometry. Our approach employs the measurement of CSF bilirubin on an automated instrument, using the Jendrassik and Gróf method, calibrated to measure lower concentrations.2 We found that at a CSF bilirubin cut-off of 359 nmol/L, based on our upper reference interval in CSF, there was 100% negative predictive value2 for a net bilirubin absorbance greater than 0.007, i.e. positive initial scan. In a follow-up study,3 the validity of this cut-off was confirmed, with no evidence from clinical records to suggest that any case of SAH had been missed. The accompanying editorial,4 acknowledged that it could thus act as an initial screening method to eliminate those samples that would subsequently prove to be negative spectrophotometrically, thereby allowing the majority of samples to be screened out by a procedure potentially available on a 24-hour basis. An added advantage is that small volumes of sample, around 100 µL (compared with 0.5 mL needed for disposable cuvettes for absorbance scans) are sufficient for the CSF bilirubin determination.3 Preliminary data suggestsome negative interference of haemoglobin on CSF bilirubin,which requires further study and quantitation, although it alsoaffects NBA derived by spectrophotometry. For operational purposes,CSF samples are also submitted to spectrophotometry if our analyserhaemolytic index is greater than 2.0 mg/dL.

We believe that this methodology should be easily transferable to similar analytical platforms, although it is imperative that each laboratory should meticulously validate its own analytical performance. It offers a robust test and may be particularly useful in peripheral laboratories as a screen to identify those samples that need to be confirmed by spectrophotometry.3


C M Florkowski,
S J Southby and
P M George


Canterbury Health Laboratories, PO Box 151, Christchurch, New Zealand




REFERENCES

Go to previous sectionTop

 REFERENCES


  1. Cruickshank A, Auld P, Beetham R et al. Revised national guidelines for analysis of cerebrospinal fluid bilirubin for bilirubin in suspected subarachnoid haemorrhage. Ann Clin Biochem 2008;45:238–44[Abstract/Free Full Text]
  2. Chao C-Y, Florkowski CM, Fink JN, Southby SJ, George PM. Prospective validation of cerebrospinal fluid bilirubin in suspected subarachnoid haemorrhage. Ann Clin Biochem 2007;44:140–4[Abstract/Free Full Text]
  3. Ungerer JPJ, Southby SJ, Florkowski CM, George PM. Measurement of cerebrospinal fluid bilirubin in suspected subarachnoid hemorrhage. Clin Chem 2004;50:1854–6[Free Full Text]
  4. Beetham R. CSF bilirubin-spectrophotometry or direct measurement? Ann Clin Biochem 2007;44:99–100[Free Full Text]


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What’s this?






This Article
Right arrow

Full Text (PDF)

Right arrow
All Versions of this Article:

acb.2008.081101v1

45/6/617

most recent

Right arrow
Alert me when this article is cited
Right arrow
Alert me if a correction is posted
Services
Right arrow
Email this article to a friend
Right arrow

Similar articles in this journal

Right arrow
Similar articles in PubMed
Right arrow
Alert me to new issues of the journal
Right arrow
Download to citation manager
Right arrow
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow
Articles by Florkowski, C M
Right arrow
Articles by George, P M
Right arrow Search for Related Content
PubMed
Right arrow
PubMed Citation
Social Bookmarking

What’s this?