title: Evaluation of a test for its suitability in the diagnosis of variant Creutzfeldt-Jakob disease.
abstract: OBJECTIVE
  Evaluation of variant Creutzfeldt-Jakob disease (vCJD) diagnostic/donor screening tests is made complicated by the very limited supply of blood samples from clinically confirmed cases of vCJD. To determine appropriate access for test developers to rare Creutzfeldt-Jakob disease (CJD) blood samples, the oversight committee of the NIBSC CJD Resource Centre has developed a process and protocols detailing minimum requirements for both test sensitivity and specificity. This protocol is broadly similar to that outlined in the common technical specification (European Directive 98/79/EC).
  
  
  METHODS
  Tests are subjected to a stepwise evaluation (step 1). vCJD tissue homogenates spiked into pooled human plasma (step 2). Blood samples from animals known to be incubating (Transmissible spongiform encephalopathy) TSE disease (scrapie/Bovine Spongiform encephalopathy (BSE)-infected sheep, BSE-infected primates) and appropriate controls (step 3). Fresh or frozen plasma from normal UK blood donors and (step 4). Plasma samples from individuals with confirmed clinical stage variant CJD (transfusion transmission) or sporadic CJD (no evidence of blood transmission).
  
  
  RESULTS
  The assay evaluated performed with good sensitivity with vCJD-spiked tissue homogenates, poor sensitivity for ovine TSE-infected blood samples and failed with plasma from BSE-infected non-human primates and with true vCJD clinical samples.
  
  
  CONCLUSIONS
  The test evaluated here is currently unsuitable for use in blood donor screening or diagnosis using blood.
authors.affiliation: CJD Resource Centre, National Institute for Biological Standards and Control, Hertfordshire, UK.
authors.forename: J K
authors.initials: JK
authors.lastname: Cooper
authors.forename: N
authors.initials: N
authors.lastname: Andrews
authors.forename: K
authors.initials: K
authors.lastname: Ladhani
authors.forename: E
authors.initials: E
authors.lastname: Bujaki
authors.forename: P D
authors.initials: PD
authors.lastname: Minor
mesh_terms: D000818:Animals; D001782:Blood Donors; D002417:Cattle; D007562:Creutzfeldt-Jakob Syndrome / Q000097:blood* / Q000175:diagnosis* / Q000635:transmission; D046148:Donor Selection / Q000379:methods*; D016643:Encephalopathy, Bovine Spongiform / Q000097:blood / Q000175:diagnosis / Q000635:transmission; D005260:Female; D006403:Hematologic Tests / Q000379:methods*; D006801:Humans; D010949:Plasma / Q000737:chemistry; D011323:Primates; D012608:Scrapie / Q000097:blood / Q000175:diagnosis / Q000635:transmission; D012680:Sensitivity and Specificity; D012756:Sheep; D065227:Transfusion Reaction
keywords: blood collection, Prions, transfusion, transmissible infections