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 · updated 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). 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 revised and expanded on the same date.

Scope: the revised <88> and <87> are written for packaging systems for drugs and for packaging of combination products regulated by FDA's drug center (CDER). For medical devices, and for combination products regulated as devices, both chapters refer readers to FDA's device guidance (revised <88>, revised <87>). For device biocompatibility that means the biological evaluation framework of ISO 10993-1 described in FDA's ISO 10993-1 guidance. USP does not present ISO 10993 as a replacement for Class VI. ISO 10993-1 was already the device framework.

Existing data: the change does not invalidate Class VI testing already performed. Industry commentary describes it as historical evidence that can still support a material's safety documentation where appropriate (Saint-Gobain; see also ISPE). What ends is USP's Class VI designation for new claims.

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 data it will provide after December 1, 2026 (for a device, typically ISO 10993 test reports; USP <87> data where relevant) and base the device evaluation on ISO 10993-1. See also USP Class VI vs ISO 10993.