Top 3 common Biocompatibility testing pitfalls for medical devices

Biocompatibility testing for medical devices is governed by the ISO 10993-1 standard. This standard gives clear guidance on how medical devices are to be evaluated to ensure they are safe for contact with patients.

To avoid regulatory challenges and potential safety hazards for a device, a thorough analysis of ISO 10993-1 must be applied to the device under development. Here is a list of the most common biocompatibility testing mistakes and misunderstandings we encounter:

1. Not using a risk-based approach

ISO 10993-1 provides a convenient testing matrix table as a reference for the appropriate testing to be performed for medical device evaluation. However, this table is not simply a checklist— the appropriate testing regimen must be governed by an overall preliminary risk assessment. Sometimes, less testing is appropriate due to the nature of the device, established biocompatibility literature and characterization for materials used, etc. Other times, additional testing beyond the minimum requirements of the standard or specific test methods are warranted. A thorough preliminary biocompatibility risk assessment will take into consideration all of the materials of the device which are patient contacting along with the intended use of the device, review established literature and precedents for material safety, and make recommendations for the testing and analysis that is appropriate for the device.

2. biocompatibility only evaluates patient contacting materials

Not all parts of a medical device must be tested for biocompatibility. ISO 10993-1 clearly indicates that patient-contacting materials are within scope. In some cases, only a specific portion of the device (e.g. a catheter) is within the patient and the remaining portion of the device is only in contact with the physician. In other instances, a complex medical device is enclosed in a protective housing and only the plastic housing is handled by the patient. This strategic mindset can help focus how test articles are prepared for evaluation. Once again, a risk-based approach must be used to consider the nature and extent of how a particular device is intended to be used.

3. biocompatibility testing need not consider design failures or use failures

Errors by the physician or mechanical failure of the device can result in a change in time duration or extent/nature of exposure of the device to the patient. These hazardous conditions and the appropriate mitigations should be covered in the risk management file of the device (i.e. typically a Use FMEA or Design FMEA). However, compliance with ISO 10993-1 does not expressly require the biocompatibility evaluation of devices under failed conditions. Other mitigation techniques may be more effective and more appropriate including inherent safety by design, instructions and labeling, etc.

An informed, strategic approach to ISO 10993-1 compliance and biocompatibility testing can save both time and money during medical device development.