(HealthDay News) — A prototype blood-based assay shows high specificity for variant Creutzfeldt-Jakob disease (vCJD), according to a study published online March 3 in JAMA Neurology.

Graham S. Jackson, PhD, from University College London, and colleagues used blood samples from national blood collection and prion disease centers in the United States and United Kingdom to determine the diagnostic accuracy of a prototype blood test for vCJD. The sample cohort included 5,000 samples from the U.S. blood donor population; 200 from healthy U.K. donors; 352 from patients with nonprion neurodegenerative diseases; 105 from patients for whom a prion disease diagnosis was likely; and 10 from patients with confirmed vCJD.

The researchers found that the assay’s specificity was 100% among the presumed negative U.S. donor samples and in the healthy U.K. cohort. No samples tested positive among the potentially cross-reactive blood samples from patients with nonprion neurodegenerative diseases (100% specificity). Two patients with sporadic CJD tested positive among those for whom a prion disease diagnosis was considered likely (98.1% specificity). In a small blind panel of samples from unaffected individuals and patients with vCJD, the sensitivity was 70%.

“In conjunction with the assay’s established high sensitivity (71.4%), the extremely high specificity supports using the assay to screen for vCJD infection in prion-exposed populations,” the authors write.

Two authors disclosed financial ties to D-Gen Ltd., a company working in the field of prion disease diagnosis.

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