This novel form of multiplexing allows the user to probe for multiple targets and simultaneously identify a specific target. An example of solutions provided here comprises: providing one or more assay mixes for a number of targets (the number of assay mixes is less than the number of targets); providing a number of reference patterns (each of the reference patterns is associated with one of the targets); contacting each of a number of aliquots with one of the assay mixes; generating a result pattern, based on positive or negative results; and selecting the reference pattern most similar to the result pattern, to thereby detect the target. Differential multiplexing with pattern recognition may involve molecular or immunological techniques to identify one of many indicators of drug use, illness, disease, or medical condition.