The use of “stand-alone symbols” or symbols without corresponding explanatory text in medical device instructions offers several key benefits including:
· an increase in the salience of the instructions;
· rapid communication of important information;
· overcoming language barriers; and
· space savings in instructional materials.
Unfortunately, non-standardized labeling practices in the medical field place a burden on healthcare professionals (HCPs) to remember the meaning behind the symbols being used to convey important information. To compound this issue, the meaning behind similar symbols can vary from one manufacturer to the next. Worse, the symbols used by a manufacturer for one product may differ from the symbols used for another of their products. And sometimes when an existing product is updated the symbols are re-designed, increasing the potential for use-related risk.
In an attempt to remedy this issue and harmonize the U.S. device labeling requirements with international regulatory requirements (e.g., ISO 15223-1:2021 and BS EN 980:2008), the FDA has issued a final rule that revises its “medical device (and certain biological product) labeling regulations to explicitly allow for the optional inclusion of graphical representations of information, or symbols, in labeling (including labels) without adjacent explanatory text”.
What changed and what does this mean for manufacturers?
Prior to the release of the final rule, manufacturers selling devices in the US were prohibited from using symbols without adjacent explanatory text. Now, the Agency allows the use of those symbols with the requirement that they are explained in a symbols glossary (paper or electronic) included in the labeling for the medical device, and if one of the following requirements are met:
1. The symbol is established in a standard [that] is recognized by the FDA, or
2. The device manufacturer determines that the symbol is likely to be read and understood by the ordinary individual under customary conditions of purchase and use.
A symbols glossary is not required for symbols used in labeling with adjacent explanatory text.
Symbol recognition and understanding should be included in usability testing for medical devices if a manufacturer chooses to use symbols that are not established in a standard recognized by the FDA.
Benefits of the final rule
The most noteworthy benefits of this new ruling include:
· Cost savings over time
· Space and cost savings in instructional materials
· Increased user recognition and comprehension
· Alignment with EU/worldwide regulations
The annual net benefit to manufacturers across the US is estimated to be between $6.6m - $22.3m.[3, 4] These cost benefits are derived from estimates based on current design and re-design practices, which are expected to be replaced by a one-time cost to re-design the labeling in accordance with the final rule, a one-time cost for creating the glossaries, and a recurring cost of revising the glossaries.
More importantly, standardization of stand-alone symbols promises to relieve some of the demand put on HCPs to continuously re-learn the meaning of symbols. While current HCP comprehension level for standardized symbols is still questionable4, streamlining their use in the long run could have a positive effect on user comprehension.
Overall, the change harmonizes the U.S. with existing international labeling requirements (as defined in the recently revised ISO-15223-1:2021) and allows domestic device labels to be consistent with those used on devices marketed in Europe and other regions.
Some examples of internationally recognized symbols include:
Because the final rule is an optional action for manufacturers who are trying to improve usability and save cost, there are no direct drawbacks to be expected. From a human factors standpoint, manufacturers should thoroughly evaluate the impact of changing their current labeling to standardized stand-alone symbols before implementing the change to help avoid end-user misinterpretation. This evaluation can be achieved by incorporating comprehension tests as part of the usability testing for the device.