A major problem in attempting to deal with prion diseases in humans and livestock has been, and to some extent still is, the paucity of practical and sensitive clinical assays for routine detection of prions. To date, most of the assays directed toward prion detection primarily use brain tissue as the primary sample type. The principles of the present tests include western blot, ELISA, optical fiber laser immunoassay, and thioflavin T (ThT) detection. Turnaround time averages around 90 hours.
An assay has recently been developed that is bringing ultrasensitive prion detection into the realm of practical application. This assay known as RT-QuIC (Real-Time Quaking-Induced Conversion) is a highly specific antemortem assay that can be performed without a brain biopsy. Thus far, evaluations indicate this enhanced assay appears to be very sensitive and has quantitative attributes. The use of cerebral spinal fluid, and possibly the use of blood and serum in the future, makes an earlier diagnosis more real (30 hours vs. 90 hours), and the possible capability of testing blood could help prevent possible transfusion-based transmission of prion diseases. The assay is applicable for the diagnosis of Scrapies, Chronic Wasting Disease, and Bovine Spongiform Encephalopathy (BSE) in addition to CJD. Improved antemortem diagnostic testing would have significant importance in the prevention of iatrogenic transmission. Because routine disinfection procedures are not 100% adequate for CJD, there is a risk of hospital exposure from contaminated surgical/medical instruments.
