Over the past decades, antibody-drug conjugates (ADC) have become an increasingly important therapeutic modality in biopharmaceutical industry. Currently, there are 13 approved ADCs, and many more under evaluation in clinical trials. ADCs are designed to improve therapeutic index (TI) by targeted payload delivery to increase efficacy and limit the payload off-target toxicity. While most ADCs consist of antibody, linker and payload, ADCs can be designed to carry various payloads to different targets and release the payload through a plethora of mechanisms. Due to the structural complexity of ADCs, multiple bioanalytical assays can be applied to ADC characterization and the understanding of ADC pharmacokinetic properties and payload deconjugation rate, including total antibody, ADC, and unconjugated payload using either ligand binding assay (LBA) or liquid chromatography-mass spectrometry (LC-MS) based assay (Table ). While LBA method requires anti-payload for intact ADC quantification, LC-MS based method can bypass this limitation. Furthermore, for DAR-sensitive quantification of ADC concentration, LBA-methods require that capture and detection efficiency be DARdependent, whereas for LC-MS-based methods actually require the converse assumption to ensure accurate DAR quantification.