Lipophilic contamination from manufacturing persists invisible to water-based testing yet accumulates in fatty tissues causing systemic toxicity or interferes with cellular membranes triggering unexpected biological responses discovered only after expensive biological testing. Non-polar extraction using hexane followed by GC-MS analysis targets lipophilic contaminants including hydrocarbon residues from machining, non-polar plasticizers providing material flexibility, and hydrophobic additives preventing material degradation that water and isopropanol extractions miss entirely. Following ISO 10993-12 and 10993-18 requirements, this aggressive extraction ensures detection of substances that could accumulate in fatty tissues through lipid partitioning or interfere with lipid membranes causing cellular dysfunction. Critical for devices containing rubber components where non-polar additives including sulfur accelerators and antioxidants prevent degradation but migrate causing sensitization, metal devices with hydrocarbon lubricants from manufacturing requiring removal before sterilization, and any device where lipophilic contamination affects biocompatibility through membrane interactions or tissue accumulation. The comprehensive screening identifies unexpected non-polar contaminants from supplier changes introducing new additive packages, manufacturing variations where process modifications leave different residue patterns, or material interactions where components exchange additives during storage creating contamination absent from individual materials. The hexane extraction aggressively solubilizes hydrophobic substances providing worst-case assessment of potential exposure, supporting toxicological risk assessment calculating safety margins based on maximum possible leaching. For implantable devices, non-polar extractables assessment becomes critical because lipophilic compounds accumulate in adipose tissue surrounding implants, creating chronic exposure scenarios requiring comprehensive characterization and risk evaluation demonstrating patient safety.