Assays for measurement of biologicals
The measurement of biologicals in clinical samples faces different challenges from traditional small molecules assays, some of which are obvious given their large and complex structures. Ligand-binding assays, both commercially available and in-house developed, have been used for quantifications of mAbs, including several among the ones relevant in transplantation [2-4]. These methods can also be adapted to or complemented with assays for the detection of anti-drug antibodies (ADA) [3, 5]. Recent technological advances in mass spectrometry based analysis (LC–MS/MS) have enabled the development of multiplex bioanalysis which means that several mAbs can be analysed in the same setup [6], as exemplified for some of the drugs that are discussed in the following [7-10]. The detailed discussion of the analytical challenges and pitfalls are beyond the scope of this paper, and readers are referred to the cited reviews for details.