It will be important for additional studies to determine more precise estimates of the tests’ specificities, which are necessitated by the wide confidence intervals reported, because the tests can lead to breakthrough false-positive results.
CJD “is extremely uncommon, and a test without near-perfect specificity may also result in many false positive results if it is applied to patients with a low probability of having the disease,” said Dr. Masters. “In these circumstances, it is important to highlight the preliminary nature of these studies.”
Moreover, the finding that abnormal prion protein seeds are found in the olfactory mucosa “at concentrations equivalent to those in diseased brain, and several logs greater than those in CSF,” has implications for infection control. “Some experts have [already] recommended appropriate decontamination of surgical instruments that come into contact with the olfactory epithelium of patients at high risk for CJD,” he concluded.
—Mary Ann Moon