Limitations of Stand-Alone Symbols in Labeling

By Eric F Shaver, PhD

With the publishing of the FDAs Use of Symbols in Labeling final rule earlier this year, many companies are looking to incorporate “stand-alone symbols” (symbols without corresponding explanatory text) in medical devices labeling. This is understandable because symbols have the potential to:

  • increase the salience of labeling,
  • rapidly communicate important information,
  • overcome language barriers, and
  • require less real estate than written communication.

But, symbols aren’t a panacea for all device labeling challenges – especially if they’re not understandable. A recently published article in Packaging Technology and Science by Seo, et al (2016) highlights this important point.

The authors had 86 healthcare providers evaluate 38 symbols from AAMI/ANSI/ISO 15223-1, a consensus standard currently recognized by the FDA. Participants were asked to provide a meaning for each of the symbols. Comprehension was determined by two reviewers evaluating the responses using one of five categories: (1) correct; (2) wrong; (2b) wrong and the response given is the opposite of the intended meaning; (3) the response given is “Don’t know;” and (4) no response is given. The researchers then used an acceptance criteria based on ANSI Z535.3 (85% successful comprehension with less than 5% critical confusions) to determine whether each symbol was “successful” or “unsuccessful.”

The results demonstrated that only six of the thirty-eight symbols tested (Non-Sterile; Contains or Presence of Natural Rubber Latex; Batch Code; Sterile; Catalog Number; and Caution, Consult Accompanying Documents) successfully met the acceptance criteria. Interestingly, five of the six symbols incorporated text in the visual. Moreover, four of the symbols (One-Way Valve; Sample Site; Fluid Path; Liquid Filter with Pore Size) garnered 0% comprehension.

Given this information, what’s a company supposed to do?  While it might be tempting to incorporate stand-alone symbols in the medical device labeling and be done with it, unfortunately, it’s not quite that simple. It’s important to understand whether the intended users of your product will comprehend the intended message of the symbols you plan to incorporate in your labeling. This can be determined by testing with prospective users.  If the symbols under evaluation meet an ANSI Z535.3 type threshold, great.  If not, then you should consider providing corresponding text that reinforces the symbols message in order to maximize comprehension.


AAMI/ANSI/ISO 15223-1: 2007/(R)2012 and A1:2008/(R)2012. Medical devices – Symbols to be used with medical device labels, labeling, and information to be supplied – Part 1: General requirements. Arlington, VA: Association for the Advancement of Medical Instrumentation.

ANSI Z535.3-2011. American national standard criteria for safety symbols. Rosslyn, VA: National Electrical Manufacturers Association.

Seo, D.C., Landoni, M., Brunk, E., Becker, M.W., & Bix, L. (2016).  Do healthcare professionals comprehend standardized symbols present on medical device packaging?: An important factor in the fight over label space. Packaging Technology and Science. Advance online publication. 10.1002/pts.2199.

Use of Symbols in Labeling, 81 Fed. Reg. § 115 (June 15, 2016).