Compositions are disclosed. One embodiment of a composition comprises a first antibody having an affinity for an antigen and a second antibody having an affinity for the first antibody, wherein at least one antibody is conjugated to a marker, and wherein the antigen is not present in the composition. Further disclosed are methods of using compositions according to the invention for analyzing a biological sample by antibody profiling for identifying forensic samples or detecting the presence of an analyte. In embodiments of the invention, the analyte is a drug, such as marijuana, cocaine, methamphetamine, methyltestosterone, or mesterolone. Forensic samples are identified by comparing a sample from an unknown source with a sample from a known source. Further, an assay, such as a test for illegal drug use, may be coupled to a test for identity such that the results of the assay may be positively correlated to the subject's identity.
CONTRACTUAL ORIGIN OF THE INVENTION
 The United States Government has rights in the following invention pursuant to DE-AC07-05ID14517 between the United States Department of Energy and Battelle Energy Alliance, LLC.