Radiofrequency Interference in the Clinical Laboratory

Abstract

Objectives Radiofrequency interference (RFI) is a known medical device safety issue, but there are no documented cases of interference resulting in erroneous laboratory results. Methods We investigated unexpected failure of a hematology analyzer resulting in erroneous WBC counts. Hardware failure was initially suspected, but temporal association with increased power output from a nearby antenna prompted investigation for RFI. Results Power output from an antenna located approximately 4 feet from the analyzer was increased to ensure sufficient signal for emergency communications in the building. Interference from the antenna resulted in aberrant side scatter and abnormal WBC counts. Powering down the antenna returned the instrument to normal working conditions. Conclusions We have shown RFI as the root cause of erroneous WBC counts in a hematology analyzer. We propose that RFI should be on the list of potential interfering mechanisms when clinical laboratory instruments generate inconsistent or unreliable results.