The U.S. Food and Drug Administration (FDA) recently issued the final guidance, “Electromagnetic Compatibility (EMC) of Medical Devices: Guidance for Industry and Food and Drug Administration Staff,” which details the information that should be included in premarket submissions to show EMC for electrically powered medical devices and medical devices with electrical or electronic functions, including IVDs. It is nearly identical to the draft guidance of the same name issued on November 17, 2020, which it replaces. It also supersedes the briefer 2016 final guidance “Information to Support a Claim of Electromagnetic Compatibility (EMC) of Electrically-Powered Medical Devices.” The final guidance takes effect June 6, 2023 for in vitro diagnostics, and August 5, 2022 for all other devices.
EMC information for premarket submissions
The final guidance recommends that medical device manufacturers describe all EMC-related device characteristics, such as:
- an overview of the device and its functions and modes;
- a description of the power supply;
- a statement regarding the environments in which the medical device is intended to be used;
- a description of any wireless technology used with the device; and,
- a description of any intentional radiofrequency (RF) emitters in the medical device that could be sources of electromagnetic (EM) disturbances to which a device may be exposed. We note, however, that certain emitters commonly found in some use environments might not be adequately addressed by FDA-recognized consensus standards, including radiofrequency identification (RFID) readers, electronic security systems (e.g., metal detectors, electronic article surveillance), near-field communications (NFC) systems, wireless power transfer (WPT), Cellular 5G, and unique medical emitters such as electrocautery, MRI, electrosurgical units, and diathermy equipment.
FDA also recommends manufacturers provide a summary in premarket submissions describing the potential risks associated with “malfunction, disruption, or degradation” of the performance of the medical device caused by EM disturbances that could cause harm to the patient, user, or operator of the device.
FDA recommends providing a clear statement of the device’s “Essential Performance,” which the final guidance defines as “performance of a clinical function, other than that related to Basic Safety, where loss or degradation beyond the limits specified by the manufacturer results in an unacceptable risk.” Essential Performance should be specific to each medical device and be determined by assessing the risk to the patient. While FDA acknowledges that it is possible for a medical device to have no Essential Performance, stating “no Essential Performance” in a product submission requires a scientific justification, which, in our experience, is frequently challenged by the Agency. Even for medical devices that have no Essential Performance, appropriate immunity pass/fail criteria are still required.
FDA recommends that immunity pass/fail criteria are specified in detail in premarket submissions and are: (1) quantitative, (2) specific to the medical device and functions, and (3) observable. Immunity pass/fail criteria can be different for transient EM phenomena and for continuous EM phenomena. For transient phenomena, it might be acceptable that the medical device provides the specified performance after application of the test disturbance. A recovery time can be acceptable and should be specified based on the risk analysis. For continuous phenomena, the medical device should provide the specified performance during and after application of the test disturbance.
Medical device configuration and functions tested
The guidance recommends that manufacturers provide a detailed description of the medical device being tested, including the device’s “configuration, functions, modes, and settings.” Medical device that can operate in battery power mode and in mains power mode should be tested in both modes. Additionally, batteries with embedded electronic circuitry (i.e., smart batteries) that are intended to be handled by the user should be removed from the medical device and tested separately for immunity to ESD due to the potential of ESD damaging the circuitry of the battery. In addition, patient simulators should be used where specified by the referenced EMC consensus standards or as appropriate for the medical device. Finally, wireless technology should be “on” and communicating with other medical device subsystems or ancillary equipment during EMC testing.
The final guidance recommends manufacturers perform testing on their final finished product. When leveraging EMC test results from a prior or different medical device model/version to another model/version, FDA advises that sponsors:
- identify and summarize all modifications or changes from the previously tested medical device and include any changes in the medical device’s indications, intended use, and intended use environments;
- provide an analysis of whether each modification could affect EMC of the medical device; and,
- assess whether the consensus standard used for the prior EMC testing has been superseded/replaced by a revised version.
In addition, if non-medical equipment (such as mobile phones, tablets, or computers) is used in a medical system and could affect the ability of the medical device to meet the immunity pass/fail criteria, the non-medical equipment should also be tested as part of the medical device system.
Results of EMC testing
Device manufacturers should provide FDA a summary of EMC testing that shows the product’s emissions and the immunity to EM disturbances at test levels appropriate for the medical device’s intended use environments. Pass/Fail criteria should be expressed in terms of limits, against which the medical device’s measured emissions are compared and should not exceed. In addition, results for each immunity test performed – such as electrostatic discharge, voltage dips, or radiated immunity – should include any degradations that were observed during and after each immunity test. All degradations should detail how the medical device continued to meet the immunity pass/fail criteria and if any additional mitigations need to be implemented.
If the device was modified or altered to pass the EMC testing, such as after initial EMC test failure, then the guidance recommends providing:
- A description of all changes or modifications that were made to the medical device in order to pass EMC testing.
- A statement whether the provided EMC test results occurred before or after the modifications were incorporated into the medical device.
- A statement indicating that the changes will be incorporated into the final finished medical device prior to marketing;
- An analysis as to whether these modifications might impact other aspects of the medical device safety or performance.
The guidance also details specific labeling recommendations and what EMC information is needed to support investigational use of a device as there are often iterations to the design of the medical device during a clinical study, and thus comprehensive EMC testing to consensus standards might not be the least burdensome approach to demonstrate EMC.
The final guidance is not in effect until June 6, 2023 for in vitro diagnostics (IVDs), and August 5, 2022 for all other devices. This aims to provide medical device makers time to fully operationalize the policies; for example, updates to eSTAR are needed. However, prior to these effective dates, medical device manufacturers will need to make sure they are in compliance with the final guidance.