A method for determining a presence or absence of one or more target analytes in a sample includes contacting the sample with an array of particles comprising at least first and second particle subsets disposed therein with a known particle number ratio with respect to each other. The first particle subset has at least one binding site configured to bind with a first target analyte and the second particle subset has at least one binding site configured to bind with a second, different target analyte. Changes are detected in a detectable signal emitted by the particles after contacting the sample with the array. A number of the particles that emit the change in the detectable signal are counted and this number is compared to the known particle number ratio of the subsets so as to determine the presence or absence of the one or more of the target analytes.