This article presents a comprehensive review and practical guide to the bubble point test for filter integrity in membrane filtration systems. It covers the fundamental principles, theoretical background, and standard testing procedures used to determine the largest effective pore size of various membrane types, including PES, PVDF, Nylon, and PTFE. Factors affecting test accuracy, such as wetting fluid selection, membrane material, temperature, and operator technique, are analyzed. The study highlights the advantages of bubble point testing as a non-destructive, reliable, and reproducible method for quality control in pharmaceutical, food and beverage, and water treatment applications. Detailed discussion includes experimental validation, practical considerations for industrial implementation, and comparison with alternative filter integrity methods. This work serves as a reference for researchers, engineers, and quality assurance professionals aiming to ensure membrane filter performance and process safety. Keywords: Bubble point test; Filter integrity; Membrane filtration; Cartridge filters; Sterile filtration; Pore size testing This article is also available at: Econe Filtration