An apparatus for detecting analytes in a sample is provided. The apparatus can include: a flow cytometry system including one or more detection zones; one or more irradiation sources disposed for irradiating the one or more detection zones with radiation; at least one detector disposed for collecting charges corresponding to light signals emitted from detectable analytes in the one or more detection zones, which have been excited by the radiation, wherein at least one detector includes an output; a system coupled to the at least one detector for effecting time delay integration of the charges by accumulating the charges before reading the charges at the output of the at least one detector; and a sorting mechanism, for example, to effect flow cytometry. Methods for detecting analytes in a sample are also provided.