|
Tests |
Test frequency |
Reference range |
|
|
Arterial Blood Gas |
Heparin syringe. On ice & capped |
As required |
|
|
CSF protein |
Min 5 drops in 20ml universal |
As required |
0.15 - 0.45 g/l |
|
CSF glucose |
Fluoride oxalate send blood glucose |
As required |
60% of plasma value usually ~ 2.5 - 5.5 mmol/l |
|
Sweat test |
Sweat |
Needs pre-arrangement with the laboratory |
Cl > 60 mmol/l abnormal consistent with CF Cl 40 - 60 mmol/l equivocal results Cl < 40 mmol/L normal |
Samples for CSF xanthochromia will be analysed from Monday to Friday 09.00 a.m. to 5.00 p.m. In accordance with national guidelines, CSF samples for xanthochromia must be taken at least 12 hours after the onset of symptoms and are only appropriate for the detection of suspected sub-arachnoid haemorrhage in patients who are CT scan negative. The fourth sample in the series (minimum 1 ml) is required. This is to reduce the presence of any haemoglobin arising from the tap. Interpretation of CSF xanthochromia is technically difficult and to aid interpretation the following information is required:
Indication for lumbar puncture
Result of CT scan
Time of onset of symptoms
Time of lumbar puncture
Whether the differential diagnosis includes meningitis
A pack with the collection protocol and all the necessary Microbiology and Biochemistry tubes and request forms is available from the Biochemistry Department. The packs are also located on Ward A10. It is important that the samples are sent back by porter, in the brown envelope provided, to protect the samples from light.
If there are any problems with this please contact the Duty Biochemist on ext. 2136
Many other tests, not carried out within our own laboratory, are sent away to regional or national reference centres. Enquires about any test or investigation should be made to the Duty Biochemist.