Pathology tests database

Sample and container requirements

Plain universal tube

Minimum volume required

1 mL (minimum volume 160 µL)

Special requirements

Preferably tap #4 Protect from light Serum sample for bilirubin and total protein should also accompany the CSF sample A.S.A.P delivery to laboratory, DO NOT use pod system

Patient preparation

Patient should have had a CT scan performed prior to this investigation. Proceed to CSF tap on CT negative patients only. CSF sample should not be collected until 12hrs post onset of headache.

Sample viability

Turnaround time

4 hours

Reference range

An interpretive comment is provided by the laboratory based on the National Guidelines for Interpretation of CSF Spectrophotometry.

Clinical guidance

CSF spectrophotometry is performed to identify patients who have had a subarachnoid haemorrhage (SAH) but in whom the CT scan is negative. The spectrophotometric scan detects bilirubin in the CSF, which is consistent with a bleed into the CSF. Please refer to LabTestsOnlineUK to learn more about xanthochromia, as well as NICE NG228. https://labtestsonline.org.uk/tests/csf-analysis. https://www.nice.org.uk/guidance/ng228/chapter/Recommendations.

Notes

Specimens must be collected sequentially even if no other investigations are required. The specimen must be centrifuged and separated within one hour of collection and protected from light prior to analysis (therefore samples from Microbiology are unsuitable for this analysis). Heavily blood stained specimens are invalidated due to presence of serum bilirubin.