Dye ingress testing is commonly used to evaluate the integrity of sealed pharmaceutical containers. During the test, packages are exposed to a dye solution under controlled pressure or vacuum conditions. If leaks exist, the dye enters the container and becomes visible during inspection. This provides clear visual evidence of seal or packaging defects. Although widely used in packaging validation studies, dye ingress is considered a probabilistic method because results depend on testing conditions and visual interpretation. Pharmaceutical manufacturers often combine this method with deterministic technologies for more accurate leak detection.