Recommendations on Standards for the Design of Medical Diagnostic Equipment for Adults with Disabilities, Advisory Committee Final Report

2.5.2 Major Relevant U.S. and International Standards

2.5.2.1 International Electrotechnical Commission (IEC) Standards

IEC standards are written by experts nominated by their country’s national committees. Representatives of manufacturers, regulatory agencies (including FDA), and user groups (e.g., radiologists, physicians from other clinical specialties, physicists, technologists) constitute the groups of experts. The draft standards are reviewed globally and voted on by each national committee.

The primary standards used in the design of the MDE covered by the recommended disability access standards is the IEC 60601-1 series of standards for basic safety and essential performance of medical electrical equipment. Most MDE covered by new accessibility standards would fall into the scope of IEC 60601-1 series, a tiered set of standards that is globally recognized. It is part of the regulatory approval process for applicable medical equipment in the vast majority of countries that have a formalized regulatory approval/registration process. The U.S. developed a companion standard to IEC 60601-1, designated ANSI/AAMI ES60601-1, which contains national deviations from the general standard and country-specific requirements (i.e., additions) to the standard.

The base standard, referred to as the “general standard” in this tiered system, is IEC 60601-1, “Medical electrical equipment – Part 1: General requirements for basic safety and essential performance.” The standard focuses on electrical, mechanical, and radiation safety, as well as hazards related to temperature extremes (e.g., fire), control accuracy, fault conditions, software design, construction, and compatibility with other systems. It also looks at what is considered essential performance for the equipment.

The general standard, IEC 60601-1, is complemented by a set of “collateral” standards, designated as the IEC 60601-1-x series of standards. These collateral standards can add, subtract, and/or modify the requirements of the general standard for the specific systems and topics to which they apply. For example, IEC 60601-1-3, “Radiation protection in diagnostic X-ray equipment,” addresses the requirements for radiation safety for all X-ray equipment.

Another example of the collateral standards is IEC 60601-1-6, “Usability,” which applies to all equipment covered by the general standard. However, it maps directly to IEC 62366, “Medical devices – Application of usability engineering to medical devices,” and varies little except to identify slight differences in terminology between the two documents. Both 60601-1-6 and 62366 are process standards that describe a process for evaluating the usability (related to safety) of medical devices. These standards are becoming more widely recognized and followed.

IEC 60601-1 is also accompanied by a set of “Part 2” or “Particular” standards, designated as the 60601-2-xx series of standards. These particular standards are written specifically to address the unique aspects of one particular type of medical electric equipment. They can add, subtract, and/or modify the requirements of either the general standard or any collateral standard for the equipment to which it applies. For example, IEC 60601-2-45 applies to mammography equipment, and IEC 60601-2-52 applies to medical beds, including stretchers. Part 2 standards do not exist for all medical equipment types; for example, no Part 2 standard is specified for examination tables and chairs. When there is no Part 2 standard, equipment is typically tested only to the general standard (i.e., IEC 60601-1).

Conformance to these series of standards is accessed via testing by an Occupational Safety and Health Administration (OSHA) certified Nationally Recognized Testing Laboratory (NRTL) such as Underwriters Laboratories (UL). The NRTL authorizes the manufacturer to apply the test house’s symbol to the medical device. This certification is required by electrical inspectors prior to introducing a piece of medical electrical equipment into a medical facility. In addition, as part of its premarket notification (510(k)) clearance process and its premarket approval process (PMA), the FDA requires manufacturers to submit evidence of conformance to these standards as part of the information they provide to demonstrate that the device is safe and effective.

2.5.2.2 International Organization for Standardization (ISO) Standards

The primary standard from ISO used in the design of medical devices is ISO 14971, “Medical devices - Application of risk management to medical devices.” Risk management plays a critical and central role in the design of medical devices, and it also ties into IEC 60601-1 and FDA’s expectations for quality systems and premarket clearance or approval. Potential hazards must be identified and then assigned ratings of the probability of occurrence of harm and of the severity of the consequences of that harm. These ratings are combined to generate a risk level. If the risk level is high enough, the design must incorporate mitigations to control the risk. The risk mitigation measures must also be assessed to confirm their effectiveness at reducing the risks to acceptable levels and to ensure that they did not introduce any new hazards or risks.

2.5.2.3 FDA Standards

The FDA maintains a list of recognized consensus standards on their web site,^P which includes standards from IEC, ISO, and other organizations. Manufacturers and assemblers of systems use these standards to demonstrate that a product is safe and effective. Depending on the classification of the equipment (see Section 2.5.1), supporting evidence of compliance to the applicable performance standards may need to be submitted to the FDA for review and approval.

Notably, among the FDA’s recognized consensus standards is ANSI/AAMI HE 75,^Q recommended practices for human factors design principles for medical devices. Chapter 16 of ANSI/AAMI HE 75 contains recommended practices regarding accessibility for patients and health care personnel with disabilities.

For radiation emitting devices (such as some diagnostic imaging equipment), FDA has a set of performance standards that focus on radiation safety to the operator and patient. These are found in the Code of Federal Regulations, specifically in Title 21, Part 1020 (21 CFR 1020), Performance Standards for Ionizing Radiation-Emitting Products, and Part 1050 (21 CFR 1050), Performance Standards for Sonic, Infrasonic and Ultrasonic Radiation-Emitting Products. Manufacturers and assemblers of applicable systems must file a report to FDA that includes test data that demonstrates compliance to the applicable performance standards for the device in question.

Notes

^P This list of consensus standards recognized by the FDA is available at: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfstandards/search.cfm

^Q Information about the human factors design principles for medical devices is available at: http://www.aami.org/he75