Subvisible particle (SVP) analysis is a key indicator of stability and safety and is an essential parenteral drug quality metric. Yet assessment of SVPs is especially challenging in adenoassociated virus (AAV) vector formulations, in which limited precious sample is available. Traditional SVP methods consume large sample volumes, while dynamic light scattering (DLS), size-exclusion chromatography (SEC), and visual inspection can miss aggregates in the subvisible range entirely. This special report introduces backgrounded membrane imaging (BMI) technology as a solution for detection…