New Developments in IEC 60601 Amendment 1 & Risk Management: Part 2

Medical manufacturers live in a world where 
regulatory compliance must always be considered,
 including changes associated with IEC 60601.

Clarification of "Essential Performance"

When the 3rd Edition of IEC 60601 was published, two significant changes from the 2nd Edition were introduced: first, an expansion in the scope of the Standard from basic safety (only) to include essential performance; and second, introduction of a requirement for assessment of the risk management process applied by manufacturers in developing their medical devices.   
The impact of these two changes was far-reaching, in that the concepts associated with mitigating basic safety risks (fire, electric shock and casualty) are well understood; however the concept of essential performance was new for many, and mitigating their risks even more of a challenge.  Further complicating this situation was the fact that the 3rd Edition was the first attempt at including a requirement for performing an assessment of a process (in this case, the risk management process) in the context of a type examination test standard.  As may have been anticipated given this background, Amendment 1 was largely focused on clarifying what the authors intended with respect to assessing the essential performance of a device, as well as how to assess a risk management process in the context of a type examination standard.  
However, medical manufacturers live in a world where regulatory compliance must always be considered.  Therefore the significant changes associated with IEC 60601 and its Amendment 1 require medical device manufacturers to also acknowledge and address the regulatory context as well, especially considering the expectation of regulatory agencies world-wide for application of a risk management process throughout the product lifecycle.
In this two-part series of articles, the two significant changes associated with Amendment 1 are reviewed:
  1. Elimination of consideration of Clause 9 (of ISO 14971) on assessment of Production and Post-Production Information
  2. Clarification of “Essential Performance”
In our last article, we covered the reasons for eliminating an assessment of a manufacturers’ review of production and post-production information during a type test examination; and also explained why this does not free a manufacturer from regulatory expectations for performing such activities.  In this article in the series, we review the next significant change in Amendment 1 to the 3rd Edition of IEC 60601-1, which addresses the concept of essential performance. 
In Amendment 1 to the 3rd Edition of IEC 60601-1, Clause 4.3 on essential performance was greatly expanded in content, and requires a manufacturer to:
  • Identify the clinical performance of the device (extends beyond basic safety) necessary for achieving the intended use 
  • Specify performance limits ranging from fully functional to total loss in both normal conditions and single fault conditions
  • Assess the resulting risk, and if found to be unacceptable, identify this as Essential Performance, and
  • Introduce controls to reduce the risk to an acceptable level
The importance of this requirement cannot be emphasized enough.  This is because the foundation of any risk analysis, and thereby, the risk management effort rests on the:
  • Intended use
  • Needs of the user and patient
  • Essential performance
This is echoed by Title 21, CFR Part 820 Section 30 on design controls, establishing a clear linkage between ISO 14971, IEC 60601-1 and the regulatory requirements:
“(c) Design input. Each manufacturer shall establish and maintain procedures to ensure that the design requirements relating to a device are appropriate and address the intended use of the device, including the needs of the user and patient….”
“(d) Design output. Each manufacturer shall establish and maintain procedures for defining and documenting design output in terms that allow an adequate evaluation of conformance to design input requirements. Design output procedures shall contain or make reference to acceptance criteria and shall ensure that those design outputs that are essential for the proper functioning of the device are identified….”
However before essential performance can be determined, the intended use of the device must first be known.  To that end, IEC 60601 defines intended use as:
“use for which a product, PROCESS or service is intended according to the specifications, instructions and information provided by the MANUFACTURER”
By defining the where and how a medical device is to be used, it is readily apparent that different hazards, and potentially different classes of hazards, will arise during risk identification.  For example, a dialysis machine intended for use in a clinical setting will have a very different set of risks than a dialysis machine intended for use in a home environment.  
Consider the users.  In a clinical setting, users of a dialysis machine may be expected to be (and reinforced by accompanying documents) professionals having education, training and licensing appropriate to the risks associated with such devices.

 Additionally, ongoing professional monitoring and availability of personnel to respond to alarms may be anticipated.  Contrast this with a home setting, where users may not have a medical background, and may have cognitive or physical limitations.  Alarms and responses to alarms may also not be as timely as in a clinical setting.  Although the risks associated with the above considerations (and others) may be addressed by a device manufacturer, a home environment poses unique challenges as compared to a clinical setting.
The next step is to define what the manufacturer expects the product to do from a clinical standpoint.  For example, the product may be used to diagnose a disease or other conditions; or the product may be used in the cure, mitigation, treatment, or prevention of disease; the product may also affect the structure or function of the body.  Once the clinical function of the product is established, it becomes possible to define the essential performance.  
One way of doing this is to ask, what would happen to the patient if the product did not perform the clinical function as specified?  Is there a risk of harm?  (Of course, this must consider degraded performance of the product as well, e.g., freedom from distortion in an imaging device used for diagnosis).  If the answer to the question is yes, the patient may in fact be harmed by a failure of the product to perform the clinical function as intended; and if the risk of that harm is an unacceptable risk per the manufacturer’s acceptance criteria, then the identified performance is essential performance.
With these foundational elements in place, all later steps of the risk management process will follow.  A detailed specification of the intended use of a product establishes the contextual boundaries for risk identification.  Essential performance defines the device functions that must be preserved in all circumstances of normal and abnormal use.  These initial steps are crucial in ensuring that all inherent risks associated with a device are “in scope” of the later risk management process steps.


Amendment 1 to the 3rd Edition of IEC 60601 went a long way to addressing and clarifying the many implementation questions that arose from the ambitious and far-reaching 3rd Edition standard.  Manufacturers are still coming to terms with the impact of all these changes, which are now being enforced in stages by regulators around the world.  With more time and greater understanding of the authors’ original intent, manufacturers and patients alike should increasingly be able to enjoy the benefits of more rapid introduction of new products, and safer and more effective devices, as originally envisioned by the 3rd Edition of IEC 60601-1 and ISO 14971.

Click here to read the first part of this article that ran Tuesday, January 19. 

Mark Leimbeck is a program manager for the Medical Regulatory Advisory Services of UL’s Health Sciences Division. He is responsible for developing new services and training, and he represents UL on international standards and other technical development committees.

Leimbeck has worked with UL for over 30 years in a variety of roles, including operations manager and principal engineer for multiple product categories. He currently serves as the chair of the UL Health Sciences Council and is a member of the IECEE Risk Management Task Force.

Leimbeck is a registered professional engineer (PE) and a registered RABQSA auditor. He holds a bachelor’s degree in electrical engineering technology from Southern Illinois University and a master’s degree in business administration from the University of Chicago.