USP Plastic Class VI and ISO 10993 are not two levels of the same approval. USP <88> describes defined in-vivo biological-reactivity tests for plastics and assigns test classifications under specified extraction and exposure conditions. ISO 10993-1:2025 is a risk-management framework for planning the biological evaluation of a medical device according to its materials, intended use, nature and duration of body contact, manufacturing history and available evidence. Neither a Class VI result nor an ISO 10993 report, by itself, proves that every finished device made from that material is safe for every medical use.
For a TPE part, start with the exact commercial grade and formulation, then evaluate the finished device in its intended contact category. Supplier test data can reduce uncertainty, but it must be applicable to the supplied grade, color/additive package and processing route. The device manufacturer remains responsible for the biological evaluation and for meeting the requirements of the target market.
This article explains how to use the public information from USP, ISO and the U.S. FDA when preparing material evidence. It does not claim access to paid standards text and is not a substitute for regulatory or toxicological review.
What Do USP Class VI and ISO 10993 Actually Mean?
The two references answer different questions. A USP <88> Class VI result documents performance in a defined set of biological-reactivity tests. It is useful only when the report identifies the exact material or test article, extraction conditions, test methods and result. It is not an FDA approval and it is not a complete device biological evaluation.
ISO 10993-1:2025 describes how biological safety is evaluated within a risk-management process. The framework considers existing material and chemical information, the device’s physical and chemical characteristics, manufacturing, intended use, body-contact nature and duration, and any biological endpoints that remain to be addressed. The result can be a justified use of existing evidence, additional characterization, biological testing, or a combination; it is not automatically the same test panel for every device.
| Evidence or framework | What it can support | What it cannot establish alone |
|---|---|---|
| USP <88> Plastic Class VI report | Defined biological-reactivity results for the identified test article and conditions | Safety of every formulation, process, sterilization method or finished device |
| ISO 10993-1 biological-evaluation plan | Risk-based selection and assessment of relevant biological evidence for a device | A generic certificate that makes a resin universally suitable |
| Supplier technical and regulatory file | Grade identity, composition disclosures, change control and available test data | Device compliance when the file does not match the final formulation and use |
| Finished-device evidence | Effects of geometry, manufacturing residues, cleaning, packaging and sterilization where relevant | A substitute for documenting the raw material and manufacturing history |
Does a Medical TPE Need Both USP Class VI and ISO 10993 Evidence?
No universal rule requires every medical TPE to carry both a USP Class VI report and the same ISO 10993 test package. Requirements depend on the device, target market, contact category, contact duration, risk assessment and the evidence already available for the exact material and manufacturing route. A buyer may contractually request both, but that commercial requirement should not be presented as a universal regulatory rule.
The U.S. FDA’s September 2023 biocompatibility guidance describes a risk-based approach and asks whether additional testing is needed after reviewing the device materials, contact, prior use, processing and other evidence. FDA’s Biocompatibility Assessment Resource Center also directs sponsors to select endpoints by device contact and duration and to compare the test article with the final device, including relevant manufacturing and sterilization differences.
Before ordering tests, identify the applicable regulator and recognized standard edition, prepare a biological-evaluation plan, document evidence gaps and obtain advice from a qualified regulatory or toxicology professional. This avoids both under-testing and repeating tests that existing, applicable evidence can adequately address.
What Is the Practical Checklist for Medical TPEs?
Do not accept a one-line statement such as “medical grade,” “Class VI material” or “ISO 10993 compliant” without scope. Match every report to the exact commercial grade, formulation or representative test article, test conditions and date. Confirm whether a color masterbatch, additive, adhesive, insert, processing aid, regrind or supplier change falls outside the evidence.
| Party | Evidence to request | Decision it supports |
|---|---|---|
| Material supplier | Exact grade and color/additive identity; current TDS/SDS; composition or restricted-substance declarations available under confidentiality; USP or ISO test reports with test-article identity and conditions; sterilization/chemical-compatibility data; change-control terms | Whether supplier evidence applies to the purchased formulation and intended process |
| Molder / assembler | Lot traceability; drying, molding and contamination controls; colorant/regrind policy; mold-release or process-aid use; cleaning validation where applicable; deviation and change records | Whether manufacturing can introduce or change biological or chemical risks |
| Testing laboratory / evaluator | Accreditation and relevant scope; protocol and extraction rationale; test-article definition; controls; complete report; deviations; interpretation limits | Whether the study addresses the documented device risk and can be reviewed |
| Device manufacturer | Intended use; contact tissue and duration; patient population; manufacturing flow; cleaning/sterilization; packaging; previous evidence; biological-evaluation plan and final assessment | What evidence is applicable and what gaps remain for the finished device |
A useful supplier package should also explain how changes are notified. If the material formulation, manufacturing site or process changes, the device manufacturer should assess whether the existing biological evaluation remains applicable rather than assuming that every change requires—and every unchanged product avoids—the same testing.
How Do Cleaning, Sterilization and Manufacturing Change the Evidence?
Cleaning, disinfection and sterilization can change a polymer’s chemistry, appearance, mechanical properties or extractables profile. Evaluate only the methods and number of cycles relevant to the actual device. Steam, radiation, ethylene oxide and chemical disinfectants impose different exposures; a grade suitable for one route is not automatically suitable for another.
Manufacturing can also matter. Heat and residence history, contamination, additives, colorants, bonding agents, lubricants, mold-release agents, cleaning residues and packaging may make the finished test article different from the supplier’s plaque or raw-material sample. Where chemical characterization is part of the plan, ISO 10993-18:2020 provides a framework for identifying and quantifying constituents in materials or devices; the official ISO page states that the 2020 edition was reviewed and confirmed in 2025.
| Project input | Why it matters | How to verify |
|---|---|---|
| Body contact and duration | Drives the biological endpoints considered in the risk assessment | Document intended use, contact tissue and cumulative duration |
| Exact TPE grade and all additives | Supplier evidence may not cover a different formulation | Match purchase specification, declarations and report test-article identity |
| Molding, assembly and cleaning | Can add residues or change material chemistry | Define the final process and compare it with the tested article |
| Sterilization / disinfection | Method and cycles can affect properties and chemical profile | Use grade-specific compatibility data and test the representative final condition when justified |
| Design or supplier change | May change exposure or invalidate prior comparability | Run documented change assessment before deciding whether more evidence is needed |
Testing evidence still begins with the finished device and use. For the broader selection sequence—contact and duration, sterilization, formulation, processing and supplier records—use the medical-device plastic selection guide.
Conclusion
Use USP Class VI and ISO 10993 evidence for the questions they actually answer. Begin with the exact TPE formulation and intended device contact, then compare supplier evidence with the final manufacturing, cleaning, packaging and sterilization route. A documented risk assessment determines whether existing evidence is sufficient and what additional characterization or testing is justified; no single material certificate provides a universal safety guarantee.
For a molding review, provide the selected grade, regulatory market, contact category and duration, sterilization or cleaning route, annual volume, drawings and required traceability. Submit the project through the RFQ page; if CAD files are available, send them separately to jerry@ckmold.com after submitting the form.