Physical seal testing quantifies strength yet cannot detect certain leak types - micro-perforations, material porosity, or seal channels might pass mechanical tests while compromising sterility requiring sensitive leak detection methods. Bubble emission testing per ISO 11607 and ASTM F2096 provides sensitive leak detection through underwater pressurization revealing defects as bubble streams. Visual observation of bubble formation identifies leak locations and relative sizes, detects leaks that mechanical testing misses including material defects and micro-channels, and provides intuitive results enabling immediate assessment. Critical for validating package integrity complementing mechanical strength testing with leak detection, locating leak sources for remediation when packages fail integrity requirements, and routine quality control of sealed packages detecting integrity compromises. For sterile medical device packaging, bubble testing reveals material defects including pinholes from handling damage, seal channels where incomplete fusion creates pathways, and package design weaknesses where geometry creates stress concentrations causing cracks. The underwater pressurization methodology creates pressure differential driving air through leaks producing visible bubbles, enables controlled pressure application preventing package damage during testing, and accommodates various package types from flexible pouches to rigid trays. Manufacturing validation uses bubble testing verifying packaging processes produce leak-free seals, investigating integrity failures identifying specific defect types guiding corrective actions, and demonstrating process improvements effectively eliminate leak sources. The visual nature enables documentation through photography or video, supports training showing operators actual leak appearances, and provides evidence for regulatory submissions demonstrating package integrity validation thoroughness.