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Larry J Kricka, Michael Milone, Stephen R Master, Leslie M Shaw, Donald S Young, Rodellia Fontanilla, Treasa Smith, JoAnn Gardiner, David Cardamone, Marilyn Fleming, David G Rhoads, Effect of a Variable Magnetic Field on Clinical Laboratory Testing, Clinical Chemistry, Volume 55, Issue 6, 1 June 2009, Pages 1249–1250, https://doi.org/10.1373/clinchem.2009.123679
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Extract
To the Editor:
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 analyzers within our automation laboratory (Beckman Coulter DxI, DxC 800, LH 780, and LH 755; Ortho Clinical Diagnostics/Johnson & Johnson Vitros 950AT; Roche Diagnostics Modular Analytics P Module; Siemens UF-100; bioMérieux MDA; Siemens SMS Immulite 2500; Abbott Diagnostics AxSYM; bioMérieux mini VIDAS), in particular those that used magnetic particle–based reagents (Immulite 2500). We had replaced all cathode ray tube displays in the laboratory with liquid crystal display screens before magnet installation because the expected magnetic field was known to interfere with cathode ray tube operation.
