FDA Guidance

Human Factor Considerations for Medical Device Manufacturers

By: Alpa Patel, B.S., RM (NRCM) and Alyessa D’Ewart, MPC

AlpaPatelConsideration of human factors when designing a medical device should be a high priority. It is important that concerns regarding human factors are considered during the development phase of new medical devices. For many years, this phase of the process has been overlooked and ignored; however, great efforts have been made so that user errors are eliminated or reduced as much as possible. The FDA has released a human factors guidance document for medical device manufacturers. This document provides steps and guidance manufacturers should take to ensure new devices do not have potential for dangerous outcomes due to human error.

Risk Management

The risk management process for each medical device should include the elimination or reduction of hazards due to user error. User-related hazards generally occur when a user cannot interpret the correct use of the device or instruction for use (IFU) correctly. Human factors engineering and usability engineering should be incorporated into the risk management in the early development stages of the process to help manufacturers identify anticipated and unanticipated user-related hazards. Undertaking the human factor tasks during the early stages can help develop measures to reduce the possibility of user-related errors, and would demonstrate how the design supports safe and effective use.

When conducting the risk management analysis, it is important to consider not only the device users but also the user environment, and the user interface. Device users can range from professional caregivers, to installation and maintenance professionals, to patients and their family members. Regardless of the intended user, the device should be able to be used without potentially life-threatening errors. The characteristics of each intended user population is important to consider in the design of the device to accommodate the varying limitations of each intended user population. The user environment should also be analyzed as lighting, noise levels, equipment, and people in the room can distract users during performance.

The major factor to consider during a risk management analysis is the user interface of the device. This includes all points of interaction between the intended user and the device itself. Elements such as the size and shape, software systems, components or accessories, and how the intended user manipulates the device should be deliberately chosen to reduce the amount and severity of user-related errors. It is also important that the information and manipulation of the device is laid out in a logical sequence for the intended user. Users will expect medical devices to function similarly to other devices they have used, and disrupting this flow may cause user-related errors.

Evaluation Methods

User tasks for each medical device should be identified and categorized based on the amount of potential harm that could result from user errors in each task. The tasks should be analyzed to determine the errors a user might make, the circumstances that may cause a user error, the potential harm from the error, and how the occurrence of the error might be reduced or eliminated. Critical tasks are those where serious harm could come from the task being done incorrectly or not at all. These tasks may change as the device design is modified, so it is important to continually reassess the critical tasks. It is also helpful to identify user-related issues in similar medical devices that are already on the market. This information should be used to reduce the potential user errors that can occur with the medical device being manufactured.

Other forms or methods of evaluation of the device can utilize expert reviews and heuristic analysis to identify weaknesses in the device design and establish modifications to reduce user errors.

Empirical approaches to identifying use-related errors may also be helpful by gathering data from representatives of the intended users. Observing the representatives interacting with the device and asking questions about why decisions are made can help the manufacturer when designing a medical device for specific tasks. Interviews can also provide valuable insight to known problems with a device and to possible solutions. These evaluations are beneficial during the design phases because it can allow the manufacturer to make modifications before the device goes to market.

Eliminate or Reduction of Use-Related Hazards

User-related hazards identified in the preliminary evaluations should be reduced or eliminated as much as possible during the final development stages of the device. This can be done by modifying the design of the device to remove the hazards, incorporating protective measures in the device to avoid the hazards, and by providing safety instructions and clear training for intended users. It is important to continue to reassess the device after each evaluation and modification to ensure that the user-related hazards were addressed correctly, and new hazards were not created.


Human factors validation testing should be performed to show the device can be used by intended users, for the intended purpose, and under the intended conditions, without user errors. This testing should be sensitive enough to capture user-related errors, even if the user is not aware they have made them. The user should be able to use the device as independently and naturally as possible, without any interference or guidance they would not normally have during actual use. The validation should also show that all user-related hazards have been reduced or removed during the development stages of the device. Information gathered during the preliminary analysis of the device is used to guide the validation testing.

The validation test participants should represent the variety of characteristics of each of the intended user populations. These characteristics should include considerations such as age, functional limitations, and previous experience. Similarly, the tasks performed during the validation should include the full range of critical tasks defined in the preliminary evaluations.

Generally, human factors validation testing should be done under simulated conditions, but on occasion, the validation can be performed during actual use or as part of a clinical study. This should only be done when simulated-use test methods are not able to allow adequate evaluation of the users and the device.


Incorporating human-use factors into the design of a device is a process that should be considered from the beginning of the manufacturing phase. Reducing and eliminating user-related hazards can greatly improve the safety and efficiency of the device. Best practices include performing a preliminary risk management evaluation, modifying the design of the device to eliminate as many hazards as possible, and conducting human factors validation testing.

New US FDA Guidance on the Use of International Standard ISO 10993-1: Top 10 Changes

As anticipated, the United States Food and Drug Administration (US FDA) issued a new guidance document on the use of ISO 10993-1 on June 16, 2016. In one statement the FDA summarizes how they want to see biocompatibility for medical devices supported: “For FDA submissions, biocompatibility information for the device in its final finished form, either developed through the risk management process or from biocompatibility testing (using both in vitro and in vivo models), and/or adequate chemical characterization in conjunction with supplementary biocompatibility information that adequately address the biocompatibility risks of the device should be provided.”

The guidance document doubled in length over the previous draft – there is a lot of new information. Here are our top 10 highlights:

  1. Device Examples: This version includes more communication and examples to support device companies in their submissions. Evidence is in the 5 additional attachments and the 30 page increase over the previous draft.
  2. Practitioner Contact: Assessing risk based on practitioner contact with devices now falls under ISO 10993-1 which expands the scope beyond patient safety.
  3. Recognized Standards: Important to note US FDA references other standards that are relevant to biocompatibility testing (ASTM, OECD, ICH and USP).
  4. Risk Management Guidance: Section III Risk Management for Biocompatibility Evaluations is a new lengthy 10 page section with great examples and discussion of how to approach and assess risk.
  5. Decision Trees: As described in the document assess risk BEFORE testing begins. This should be laid out in a Biological Evaluation Plan.
  6. FDA ISO Biocompatibility Matrix Updates: FDA Modified matrix is “…not a checklist…” Added separate column for Material-Mediated Pyrogenicity.
  7. Cytotoxicity Tests: Extraction time for cytotoxicity testing is identified as 24-72 hrs extraction. This differs from ISO 10993 and possibly implies that all permanent implants should be extracted for longer periods (72 hours).
  8. Hemolysis Tests: Only indirect hemolysis testing is now allowed for devices with indirect blood contact. Complement Activation no longer requires analysis of C3a. Serum is now preferred over plasma.
  9. Genotoxicity Tests: Genotoxicity testing may be waived if chemical characterization testing and literature research indicate that a genotoxic risk does not exist. However genotoxicity testing and research cannot be used to mitigate carcinogenic risk.
  10. Pyrogenicity Tests: Pyrogenicity testing is expanded to include the Bacterial Endotoxin Test (BET) for sterile devices having direct/indirect contact with the cardiovascular system, lymphatic system or Cerebral Spinal Fluid (CSF) regardless of contact duration.

Look for our webinar early August where we will go over these highlights and so much more. The FDA is presenting a webinar on the new guidance document on July 21st. If you have any questions or concerns in the meantime, contact our Toxicology and Biocompatibility experts in the Nelson Laboratories technical consulting group.

Audrey Turley – Research Scientist

Thor Rollins – Biocompatibility Expert

Dr. Sarah Campbell – Toxicologist

Trevor Fish – Toxicologist

Dr. Matthew Jorgensen – Material Science

FDA Releases ISO 10993-1 Guidance Document

FDA released the long-awaited guidance document for international standard ISO 10993-1 this week. The guidance document represents the current thinking of FDA on the topic of ISO 10993-1 “Biological evaluation of medical devices – Part I: Evaluation and testing within a risk management process.”

Our team is reviewing the document and will provide an assessment of the changes in the near future.

The document can be found  on the FDA website via this LINK.

Quick Guide to FDA’s Draft Guidance on 3D Printed Devices

Posted in Printing Services by MDDI Staff on May 24, 2016

By: Matthew R. Jorgensen, PhD

A new leapfrog guidance from FDA gives a glimpse into the agency’s thinking on 3D printed medical devices.

On May 10, 2016, FDA released a leapfrog guidance document on the technical considerations for additive manufactured or 3D printed devices. Leapfrog guidance documents provide valuable information on what is in the regulatory pipeline and allow interested parties to have a voice in the development of FDA guidance.

Continue reading on the MDDI website for key points from the draft guidance pertaining to the testing of medical devices.


FDA Proposes Ban on Powdered Surgeon’s Gloves, Powdered Patient Examination Gloves, and Absorbable Powder for Lubricating a Surgeon’s Gloves

Sterilization-of-reusable-trayFDA is proposing to ban powdered surgeon’s gloves, powdered patient examination gloves, and absorbable powder for lubricating a surgeon’s gloves. The Agency determined that an unreasonable and substantial risk of illness or injury may occur from using these medical products and the risk cannot be corrected or eliminated by labeling or a change in labeling.

Electronic comments are encouraged for docket number FDA-2015-N-5017 RIN 0910-AH02 and can be submitted via this link.

The Federal Food, Drug, and Cosmetic Act (FD&C Act) of 1976 states that any device presenting an “unreasonable and substantial risk of illness or injury” that cannot be, or has not been, corrected or eliminated by labeling or a change in labeling must be banned. FDA has been considering banning the use of powder on gloves since 1997 when it issued the Medical Glove Powder Report. At that time, FDA decided that the benefits of using powder with surgical and patient gloves outweighed the risks. Since then, FDA has received many citizen petitions regarding the use of glove powder.

As a reaction to the 1998 petition to review its stance on the use of powdered gloves, FDA reconsidered a ban on powdered gloves in 1999. Three main factors kept the ban from taking effect: (1) A ban would not address exposure to natural latex allergens from medical gloves with high levels of natural latex proteins; (2) a ban of powdered gloves might compromise the availability of high quality medical gloves; and (3) a ban of powdered gloves might greatly increase annual costs by almost as much as $64 million over the alternative approach proposed by FDA in the “Draft Guidance for Industry and FDA Staff: Medical Glove Guidance Manual.”

FDA is yet to finalize the ban. The Agency possibly has not received all the information regarding the risks and benefits of powdered gloves, so Nelson Laboratories, Inc. is encouraging anyone who is interested in this topic to submit comments to FDA via the link above.

BIOMEDevice San Jose Focus On Biocompatibility

BIOMEDevice San Jose - Biocompatibility Training InvitationPlanning your BIOMEDevice conference schedule? Be sure to leave room for Nelson Laboratories, Inc. Nelson Labs will be offering a full schedule of biocompatibility focused lectures at BIOMEDevice San Jose, December 3 – 4, 2014, while also exhibiting in booth #321.

Bob Michaels’ recent Medical Product Manufacturing News (MPMN) Q&A interview with Nelson Laboratories’ biocompatibility expert, Thor Rollins, provides a sneak peek preview of the topics to be discussed in Rollins’ upcoming BIOMEDevice lectures. The following are excerpts from Mr. Michaels’ article, What Types of Biocompatibility Testing Do You Need To Perform? Visit qmed.com to read the complete interview.

MPMN: Please go into ISO 10993-1 and why cytotoxicity testing is used for screening medical device materials.

Rollins: Cytotoxicity testing is used for screening materials because it is sensitive. In the body, body systems help protect against cytotoxins, protect the cells to wash away any pH imbalances, or even deal with some of the concentration issues or pressures that the cells cannot handle by themselves. Thus, to determine the potential impact of cytotoxicity testing, we take the device and put it right on the cells and then bombard the cells with pH, particulates, and osmotic issues. Thus, during testing, cells are subjected to substances that may not exhibit toxicity in the patient or that could only have a toxic effect if they are present in the body in large quantities. …

MPMN: How should a medical device manufacturer decide which tests are most appropriate for a given device?

Rollins: This is the $1 million question for most of the tests that we perform. …
The amount of data required about a material and the depth of the investigation depends on the intended use of the device and the processes used to manufacture it, in addition to its function and how long it will have contact with the patient. Thus, if you have knowledge of the materials that were used to make the device and data about the potential leachable compounds, this information can be used together with a biological safety evaluation to help pool which types of testing are necessary. In other words, you take the history of the history, the processing methods used to create it, and some chemistry analysis and then evaluate all of these endpoints to help decide which testing should be performed to show that the device is safe. Thus, instead of using ISO 10993-1 as a series of checkboxes, you approach the safety assessment of the device scientifically based on several factors.

Each of Thor Rollins’ BIOMEDevice lectures is slated to focus on a different aspect of the swiftly evolving biocompatibility testing landscape, providing MedTech professionals the knowledge they need to navigate the challenges inherent in contemporary biocompatibility testing. Mark your calendar for Thor Rollins’ three Tech Theater presentations Wednesday December 3rd, and register for his Conference Presentation Thursday December 4th. To learn more visit www.nelsonlabs.com.

Half-Day BIOMEDevice Biocompatibility Lecture Series:
Wednesday December 3, 2014

  • 12:30 pm – 1:15 pm: Rethinking The Big Three: Cytotoxicity, Sensitization, & Irritation
  • 1:30 pm – 2:15 pm: The Power of Chemical Characterization to Assess Changes in Your Medical Device
  • 2:30 pm – 3:15 pm: How the New FDA Guidance on ISO 10993 Could Affect You

Biocompatibility Conference Training (BIOMEDevice registration required):
Thursday December 4, 2014

  • 2:45 pm -4:00 pm: Material Selection and Sampling Techniques for Biocompatibility ISO 10993