The disclosure provides devices, device systems, and methods for analyzing cells (e.g., blood cells) or particles in a sample. In some embodiments, the disclosure provides various devices and device systems including: a light source; a collecting lens; and one, two, or more detectors. In other embodiments, the devices and device systems include a flow cell or a cartridge device with a flow cell. In further embodiments, the disclosure provides various methods including the steps of: using a light source to emit an irradiation light; using the irradiation light to illuminate a sample flow; using a collecting lens to collect both scattered light and fluorescent light from the sample flow; and using one, two, or more detectors to detect the collected scattered light and fluorescent light. Optionally, these methods include using a flow cell to form a sample flow.