Highly Specific Blood Test Detects Creutzfeldt-Jakob Disease

A preliminary study has indicated that a blood test for infection by the prion that causes variant Creutzfeldt-Jakob disease (vCJD) has sufficient sensitivity and specificity to justify a large study comparing vCJD prevalence in the United Kingdom with a bovine spongiform encephalopathy-unexposed population.

vCJD is a fatal degenerative brain disorder thought to be caused by a misfolded protein (prion) in the brain and contracted most commonly through eating beef infected with BSE (bovine spongiform encephalopathy). Up to three million cattle in the United Kingdom may have been infected with BSE, and establishing accurate prevalence estimates through screening for vCJD infection would guide public health initiatives.

Investigators at University College of London (United Kingdom) employed a prototype test (now in clinical diagnostic use) that captured, enriched, and detected disease-associated prion protein from whole blood samples using stainless steel powder to determine the presence of vCJD infection in 5,000 blood samples from US donors, 200 samples from healthy United Kingdom donors, 352 samples from patients with non-prion neurodegenerative disease, 105 samples from patients in whom a prion disease diagnosis was likely, and 10 samples from patients with confirmed vCJD.

Results revealed that the assay’s specificity among the presumed negative American donor samples was 100%, which was confirmed in the healthy United Kingdom cohort (100% specificity). Of potentially cross-reactive blood samples from patients with non-prion neurodegenerative diseases, no samples tested positive. The test identified as positive 71.4% of the patients with vCJD.

The authors concluded that, "Most importantly, the prototype vCJD assay has sufficient performance to justify now screening a large United Kingdom population sample and at-risk groups to produce an initial estimate of the level of prionemia [prions in the blood] in the United Kingdom blood donor population. A blood prevalence study would provide essential information for policy makers for deciding if routine vCJD screening is needed for blood, tissue, and organ donations and patients prior to high-risk surgical procedures."

The study was published in the March 3, 2014, online edition of the Journal of the American Medical Association Neurology (JAMA Neurology).

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