A set of compounds that includes an active-agent labeled species and a pretargeting conjugate is disclosed. The active agent-labeled species includes a ligand coupled to an active agent. The pretargeting conjugate includes a protein conjugated to a targeting species having a targeting moiety capable of binding to an in-vivo target or a biomarker produced by or associated with the target. The protein is substantially free of a cofactor. Also disclosed are methods of administering the pretargeting species and the active-agent labeled species to a subject for diagnosing or treating a disease condition, or assessing the effectiveness of a treatment of the disease condition.