Monitoring of protein aggregation is crucial to avoid the administration of an altered drug substance to a patient. The techniques that are currently used to detect the formation of protein aggregates, e.g., Size Exclusion - High Performance Liquid Chromatography SE–HPLC = SEC) and Flow Imaging Microscopy (FIM), require a certain sample preparation and the destructive use of the protein drug product to perform the measurement. Furthermore, multiple orthogonal or complementary techniques need to be used in order to characterize the sample completely, e.g., to characterize aggregates in every possible size range such as the nanometer (<100 nm), submicrometer (100-1000 nm), subvisible (1-100 µm), visible (>100 µm) range.