Abstract: A fluorescence-assisted counting apparatus for quantitative and/or qualitative assessments of a population of fluorescently stained particles in a specimen device retaining fluorescently stained particles, wherein the apparatus includes a detector module and a light source. The detector module includes a lens, a first optical filter and a detector, wherein the detector detects a fluorescence response. The lens includes a field of view taking in at least a portion of the fluorescently stained particles within the specimen device. The light source, further including a second optical filter, shines light in a light path that encompasses at least a portion of the particles.