The U.S. FDA posted an updated template for antigen testing for the SARS-CoV-2 virus, which recommends the use of natural clinical specimens for clinical evaluation rather than contrived specimens. Clinical evaluations of an antigen test should use a minimum of 30 positive and 30 negative specimens in a blinded fashion, and should use a polymerase chain reaction test listed by the agency as a comparator. A test should demonstrate a minimum sensitivity of 80% for all sample types. For antigen tests proposed for use as a screening mechanism, the FDA recommends a study that enrolls at least 20 positive asymptomatic subjects in addition to the already-stated enrollment requirements. However, the number of positive asymptomatics can be reduced by half if the sponsor provides cycle threshold values that depict similar distributions of viral load, and add the data from the remaining 10 asymptomatics after the agency grants an emergency use authorization for the test.

Medtronic advises of problems with Interstim leads

Medtronic plc, of Dublin, said it had identified 18 reports in which the percutaneous extension connector used with Interstim sacral neuromodulation devices had migrated away from the proposed stimulator pocket during the advanced evaluation period for the device. The October 2020 health care provider notification letter issued to users in Germany was directed toward two models of the Interstim percutaneous extension units, which are used with the 978A1 and 978B1 models of the Interstim. Medtronic said an unspecified number reports of migration necessitated an additional incision to disconnect the lead from the percutaneous extension, adding that patients may be at elevated risk of procedural complications due to delays incurred during troubleshooting. Intraoperative replacement of the lead or an additional surgical procedure may be required if the chronic lead is damaged or displaced during explant of the percutaneous extension.

Palmetto eyes coverage of CT for cerebral perfusion

Palmetto GBA, of Columbia, S.C., posted a draft local coverage determination (dLCD) for the use of computed tomography for cerebral perfusion analysis, which would cover the procedure for patients with small, acute ischemic stroke caused by unilateral large vessel occlusion in the proximal anterior circulation. Coverage would be limited to services provided at stroke centers for evaluation of the appropriateness of endovascular mechanical thrombectomy, assuming several conditions, including that treatment can be commenced within 6-24 hours of the time at which the patient was at neurological baseline, assuming a certain set of inclusion/exclusion criteria as seen in the DAWN study. The time-to-procedure limit for patients who meet inclusion/exclusion criteria under the DEFUSE 3 study is 6-16 hours. Palmetto is taking comment through Nov. 7.