One of our most popular posts is “What is UPS Class VI Testing and Why is it Important?”. But did you know that while USP Class VI testing is widely used and accepted, some view as the minimum requirement a raw material must meet in order to be considered for use in a medical application? In fact, USP Class VI has been largely superseded since the release of ISO 10993 in 1995. This post will take a deeper look at what biocompatibility is and how it is defined by the International Standards Organization.

To begin, let us address just what biocompatibility is. Biocompatibility is the materials lack of interaction with living tissue or living system by not being toxic, injurious, or physiologically reactive. A material that is biocompatible does not cause an immune response in a host. One thing biocompatibility is not is chemical compatibility. It does not define how well equipment will perform in an autoclave or when exposed to SIP because humans are not generally steamed in place.
Another thing biocompatibility is not is simple. In fact, no one test can comprehensively describe a material’s biocompatibility. That’s why, through the years, several testing protocols have emerged to characterize a materials biocompatibility. One of the first guides to biocompatibility was published by the United States Pharmacopeia in 1990 was USP <88>, which includes the criteria for USP Class VI Testing.

In an effort to standardize biocompatibility testing worldwide, the International Standards Organization (ISO) developed ISO 10993. ISO 10993 is a 20-part standard that evaluates the effects of medical device materials on the body. The first part of the ISO 10993 standard, “Biological Evaluation of Medical Devices: Part 1: Evaluation and Testing” is probably the most relevant to finding a place to start determining which tests methods should be used to assess a material’s biocompatibility. The rest of the sections mostly deal with appropriate methods to conduct the biological tests suggested in Part 1.

ISO 10993 uses matrices to break medical devices down into three categories: Surface, External Communicating, and Implant and further breaks these categories into subcategories based on exposure time (limited, prolonged, and permanent). Once we identify the device category and exposure time, we can then use the ISO 10993 standard to select a recommended biologic testing protocol. ISO 10993-1 is not a formal checklist, but a guide that should be used to provide the information to get you pointed in the right direction and design a testing program.

As you can see, biologic compatibility testing is complicated and just asking “Is it USP Class VI?” is often a cop out. More detailed characterization and understanding, as outlined in ISO 10993, is essential for proper material specification and selection. Most materials today comply with both USP Class VI and ISO 10993, but few know what this really means. At Holland, we pride ourselves on having the technical knowhow and understanding to interpret the meaning of material compliance and stay abreast to any material changes or compliance issues. If you have questions about the biocompatibility of your single use component, USP Class VI or ISO 10993 standards, contact a Holland Sales Engineer today.