Melbourne Health Shared Pathology Service
Xanthochromia by Spectroscopy
Spectroscopic analysis of CSF for xanthochromia is undertaken strictly according to the following guidelines. These guidelines have been established by predominantly British biochemists in the light of their experience with the assay over recent years and incorporate the current understanding of the assay and its interpretation.
Requirements and limitations. / Suitability Checklist
  • Between the onset of symptoms and the performance of the diagnostic lumbar puncture [LP], 12 hours must elapse.
  • Only one LP per symptomatic episode is possible.
  • All possible precautions must be in place to obviate a bloody tap.
  • As well as the 3 tubes of CSF usually collected at lumbar puncture, at least 1 ml of CSF must be collected into a fourth tube. This fourth tube must be totally protected from light at all times.
  • The CSF in the fourth tube is used for the spectrophotometric assessment of xanthochromia.
  • The first three tubes required by the Microbiology Department are processed by them in the standard fashion, including the assay of protein in the CSF.
  • The specimens must NOT be delivered by pneumatic tube: only hand delivered specimens are acceptable.
  • A 5 ml blood sample must be drawn into Li-heparin at the same time as the LP; both it and the LP tubes must be delivered to the laboratory at the same time, by hand.
Thus
  • Only hand held specimens will be accepted; any specimens delivered by pneumatic tube will be declined.
  • The request slip must clearly state the time of symptom onset and the time of lumbar puncture; failure to do so will cause the request to be declined.
  • Requests to assay xanthochromia in specimens where the stated time elapse between symptom onset and LP is less than 12 hours will be declined.
  • CSF samples in which the first tube has >40,000 RBCs/μL (ie >40,000 X106 RBCs/L) cannot be used for the purpose of xanthochromia assay in the fourth tube.
  • CSF specimens lacking the accompanying plasma sample will have their reporting delayed until the required plasma sample is delivered and processed.
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Availability and turnaround
  • Specimens that arrive in the laboratory between 0800 and 1600 h Monday to Friday usually will be processed the same day.
  • Specimens received outside those hours will have the RBC count and other Microbiology work done immediately and the fourth tube of CSF will be spun immediately and will be retained, at 4o C and strictly protected from light, but will be processed the following Monday to Friday working day. Samples may be assayed outside routine hours after consultation with the Chemical Pathologist, or signed authorisation by the Neuro-surgery Registrar.
  • Turnaround, in normal working hours, will be in the order of 90 to 120 minutes from arrival of all specimens in the laboratory to reporting on CIS.

CHBIS-01,16 (30/10/09)Dr C Chiang: Oct 09 Page 1 of 1