The performance of clinical analyzers is commonly assessed under a variety of environmental conditions to set acceptable limits (e.g., temperature and humidity) for operation. We recently faced an unusual environmental challenge within our automation laboratory, namely a variable magnetic field emanating from a Niobe® Magnetic Navigation System (Stereotaxis; http://www.stereotaxis.com) being installed in the cardiac catheter laboratory immediately above our laboratory. The system contains 2 strong permanent magnets that generate magnetic fields of 0.08–0.1 T (800–1000 G) in any direction. When the magnets are in the stowed position, the maximum magnetic field is 0.2 T (2000 G). Although more prominent for other medical devices, the permissible magnetic field strength is not an environmental variable usually considered by manufacturers of clinical analyzers (1)(2).
We thus faced a multifaceted problem: On the day of the magnet delivery, we had to assess its effects on all of the analyzers within our automation laboratory, and we had to assess its effects on replacement analyzers due to be installed in the following weeks. Accordingly, we needed to assess the effects of a variable magnetic field on the accuracy and precision of the current and future clinical …