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PTD-277

Test Directory - CSF 14-3-3 and CSF S100

Clinical Indications

For the investigation of neurodegenerative disorders

14-3-3 is a normal neuronal protein and is released into the CSF in response to a variety of neuronal insults. It is a non-specific finding and 14-3-3 analysis cannot be used as a screening test for sporadic CJD. Other illnesses, which can give a positive 14-3-3 test, include:

  • Herpes simplex encephalitis and other viral encephalitides.

  • Recent cerebral infarction or haemorrhage.

  • Subarachnoid haemorrhage.

  • Hypoxic brain damage.

  • Glioblastoma

  • Carcinomatous meningitis.

  • Paraneoplastic encephalopathy.

However, it is usually a straightforward clinical matter to exclude the other possible illnesses which may give rise to an elevated 14-3-3 level. Therefore, in an appropriate clinical context, a positive test is strongly supportive of a diagnosis of sporadic CJD and a negative test is unusual. 

CSF S100 is analysed in addition to CSF 14-3-3 on all specimens.

Request Form

Combined Pathology Blood form (Yellow/Black)

Availability

Referral test: analysed by National Creutzfeldt-Jakob Disease Surveillance Unit, Western General Hospital, Edinburgh if specific criteria met. Discuss with Alison Green on 0131 537 3075 before taking sample. Samples will not be sent unless they have been discussed and agreed with the National CJD surveillance Unit.

Specific Criteria

Investigation of neurodegenerative disorders

Turnaround Time

1 week

Specimen

CSF

Volume

Minimum 1.0 mL

Container

White Capped Universal

Collection

Samples must be transported to laboratory immediately.

Causes for Rejection

Not meeting specific criteria for analysis. Delay in sample reaching laboratory.

Interpretation

The detection of 14-3-3 in the CSF has been reported to have a positive predictive value of 93% and a negative predictive value of 92% for the diagnosis of sporadic CJD, but false positives and false negatives can occur in certain circumstances. S-100b concentrations in the CSF have also been reported to be elevated in cases of sporadic CJD. CSF 14-4-3 is only detected in 50% of vCJD cases. As with all tests, results must be interpreted in the particular clinical context and all cases can be discussed with the CJD surveillance team.

Lab. Handling

Processing: Samples must be centrifuged and frozen at -80C in clinical trials freezer (CB41) immediately (within 2 hours of collection).
Referral
:  C1433 and send or BPRO and track at -80C in clinical trials freezer (CB41).
Infection control must be informed by sendaway team if a patient has had a sample sent to the National CJD Surveillance Unit in Edinburgh for testing, in line with internal guidance.


Version 1.1 / July 2015                                                                                                           Approved by: Consultant Biochemist