Abstract: Immunoassay methods and reagents for the quantification of total doxepins (i.e., E-doxepin, Z-doxepin, E-desmethyldoxepin, and Z-desmethyldoxepin) in a test sample are disclosed. The quantification of total doxepins is accomplished in an immunoassay employing antibodies and labeled reagents prepared with doxepin derivatives of the Formula II: ##STR1## wherein Y-Z can be C=CH or N-CH.sub.2, R.sub.1 is a linking group, R.sub.2 can be H or CH.sub.3, and Q can be a detectable moiety or an immunogenic carrier material. The antibody reagent comprises antibodies which are capable of binding to total doxepins and which are produced with one or more immunogens prepared from the doxepin derivative of Formula II, and the labeled reagent is also prepared from the doxepin derivative of Formula II.

Abstract: Method and reagents for determining a compound of interest present in a test sample also containing one or more interfering compounds having substantially similar chemical structures, and otherwise analytically indistinguishable from each other, employing a pretreatment reagent capable of selectively modifying the chemical structure of one of the compounds without significantly modifying or altering the chemical structure of the other one of the compounds.

Abstract: Immunoassay methods and reagents for the quantification of total doxepins (i.e., E-doxepin, Z-doxepin, E-desmethyldoxepin, and Z-desmethyldoxepin) in a test sample are disclosed. The quantification of total doxepins is accomplished in an immunoassay employing antibodies and labeled reagents prepared with doxepin derivatives of the Formula II: ##STR1## wherein Y--Z can be C.dbd.CH or N--CH.sub.2, R.sub.` is a linking group, R.sub.2 can be H or CH.sub.3, and Q can be a detectable moiety or an immunogenic carrier material. The antibody reagent comprises antibodies which are capable of binding to total doxepins and which are produced with one or more immunogens prepared from the doxepin derivative of Formula II, and the labeled reagent is also prepared from the doxepin derivative of Formula II.