Abstract: The invention relates to systems and methods for performing one or more immunoassays on a fluid sample and performing image analysis on the fluid sample as the sample is flowing so as to obtain measurements related to one or more target analytes based on image analysis. The systems and methods include a disposable fluidic device, such as a cartridge, configured to be loaded with a fluid sample and perform one or more assays on the fluid sample. The cartridge is further configured to flow a volume of fluid sample, undergoing, or having undergone, an assay, through a portion thereof to be subsequently analyzed by an analysis instrument. The analysis instrument is configured to capture images of the fluid sample as it is flowing through a portion of the cartridge and subsequently analyze the images so as to obtain measurements of one or more target analytes within the fluid sample.