every lab,

a different answer

Problem statement

Medical devices that contact the body must undergo biocompatibility assessment to ensure they do not cause toxic, immunogenic, or carcinogenic harm. A critical component of this assessment is chemical characterization — identifying and quantifying substances that may leach from the device into the body. Despite the centrality of this testing, the FDA has identified that no existing guidance or consensus standard provides a detailed methodology for how to conduct extractables studies and chemical analysis of device extracts. This gap has caused widespread inconsistency across testing laboratories, leading to deficiencies in premarket submissions, delayed device authorizations, and uncertain safety assessments. The problem is especially acute for novel materials — advanced polymers, nanocomposites, bioresorbable materials — and for combination products.

Why this matters

Every medical device that contacts the body — implants, catheters, surgical instruments, wound dressings, diagnostic devices that draw blood — requires biocompatibility assessment, encompassing hundreds of thousands of device types. Inadequate chemical characterization exposes patients to potentially harmful leachables (residual monomers, plasticizers, degradation products) and delays device authorizations through submission deficiencies. The annual cost of biocompatibility testing deficiency-related submission delays across the device industry likely exceeds hundreds of millions of dollars.

What’s been tried and why it hasn’t worked

ISO 10993-18 provides a framework for chemical characterization of medical device materials, but it is a framework standard, not a methods standard — different laboratories interpret it differently and produce incomparable results. The FDA issued its first detailed methodology guidance in September 2024, specifically to address what the agency called the "potential cause of variability in how different labs perform analytical chemistry." However, this guidance remains draft (non-binding) and covers only extractable/leachable studies, not the full spectrum of biocompatibility endpoints. Manufacturers described the new guidance as "detailed and burdensome," revealing a substantial gap between current industry practice and what the FDA considers adequate. The FDA held a November 2024 workshop on accreditation schemes for conformity assessment in chemical analysis, exploring third-party testing frameworks, but no accreditation system has been established. Animal testing is still required for many biocompatibility endpoints, though the FDA is encouraging chemical characterization as a means to reduce animal testing.

What would unlock progress

Validated, standardized analytical methods for the most common device material classes — with prescriptive extraction conditions, analytical techniques, and toxicological thresholds — would eliminate the inter-laboratory variability that currently undermines the system. A tiered testing framework that matches analytical rigor to patient risk (longer contact duration or higher-risk body contact zones requiring more intensive characterization) would make compliance achievable for smaller manufacturers without sacrificing safety.

Entry points for student teams

A student team can work this problem entirely from the public regulatory record, with no lab and no lab budget: De Novo decision summaries are downloadable PDFs (`accessdata.fda.gov/cdrh_docs/reviews/DEN######.pdf`, indexed at the De Novo database) and every cleared 510(k) is queryable through the openFDA device API, so a team can pull the biocompatibility and materials sections for one material class — medical-grade silicone, say — and code what extraction solvent, temperature, duration, surface-area-to-volume ratio, and analytical technique each submission actually used. The output is a variance map of how ISO 10993-18 is being read in practice, which is precisely the empirical evidence standards bodies lack when they try to write prescriptive methods. A second team with access to a shared university analytical chemistry core (GC-MS and LC-MS, instruments most engineering schools own) could develop a reference material and standard operating procedure for a common device polymer such as silicone or PEEK, creating a benchmark labs could use to calibrate their workflows. The definitive version of the first study — commissioning the same material through several commercial contract labs and comparing what comes back — costs tens of thousands of dollars per material and yields proprietary reports, which makes it a sponsor's project rather than a semester's.