USP Class VI vs ISO 10993: what's the difference?

• "ISO 10993 tested" rarely means every part. Suppliers usually test a few endpoints, often cytotoxicity (-5) and sometimes hemocompatibility (-4). Ask which parts and which test articles.
• USP Class VI covers fewer endpoints than a typical device evaluation. It has no sensitization, genotoxicity or chronic toxicity data, so it rarely satisfies a device biocompatibility evaluation by itself.
• Your process changes the material. Colorants, additives, molding conditions, cleaning and sterilization can all change what extracts from a part. Resin data supports your evaluation; it doesn't replace it.
• Statements are tied to a grade and a date. Request the current certificate or compliance letter for the exact grade, and note the supplier's change-notification and healthcare policies.
• USP <88> changes on December 1, 2026. The revised chapter removes the Class I to VI classification; see the section below.

USP <88> changes on December 1, 2026

Added 2026-10-17

USP has revised general chapter <88> Biological Reactivity Tests, In Vivo. USP's notice gives December 1, 2026 as the date the revised chapter becomes official (USP-NF notice of intent to revise). The revision removes the chapter's classification of plastics into Classes I to VI, so from that date USP no longer defines a "Class VI" designation. Of the three in vivo tests in the current chapter (systemic injection, intracutaneous and implantation), only the systemic injection test remains, and USP <87> (in vitro biological reactivity) is expanded at the same time. Industry summaries of the change: ISPE, Saint-Gobain.

What this means for MedResin data: 185 of the 338 public grades list USP Class VI in their cited supplier literature. Those entries record what the supplier stated about testing done under the chapter as it stood; we keep them as stated and will update them as suppliers revise their documents. For new specifications, ask the supplier what biocompatibility statement it will provide after December 1, 2026 (for example USP <87> or ISO 10993 test reports), and base the device evaluation on ISO 10993-1, as FDA's guidance describes. See also USP Class VI vs ISO 10993.