Particle detection cartridges are provided. Aspects of the particle detection cartridges according to certain embodiments include a sample input, a flow channel and a light channel, where the flow channel and light channel are coupled at a detection region such that only light from the detection region can propagate directly through the light channel to a detector. Systems including the cartridges, as well as methods for detecting particles in a sample with the subject particle detection cartridges/systems, are also described. Kits having one or more cartridges are also provided.