Leak Testing and DOP Challenge: A Complete Guide Complete Guide to HEPA Filter Leak Testing and DOP Challenge in Pharma High-Efficiency Particulate Air (HEPA) filters are a cornerstone of contamination control in pharmaceutical cleanrooms and sterile manufacturing areas. Ensuring their integrity through leak testing and DOP (Dispersed Oil Particulate) challenge is not only a GMP requirement but a critical quality control measure. Regulatory agencies like the FDA, EMA, and ICH emphasize HVAC system performance qualification as a core component of environmental control strategy. This guide provides a step-by-step, regulation-compliant approach to HEPA filter leak testing using the DOP challenge method….