Quantification of proteins in whole blood, plasma and DBS, with element-labelled antibody detection by ICP-MS

Over recent years, quantification of multiple proteins in body fluids has become increasingly prominent, which is beneficial to a number of scientific fields, not least biomedical. Several techniques have been developed based on conventional ELISA; one of these techniques is analysis of proteins labelled with element-tagged antibodies by ICP-MS in serum, allowing quantification of multiple targets within a single sample. This research aimed to quantify albumin and immunoglobulin G (IgG) levels in plasma, whole blood and dried blood spots using NANOGOLD^® and Europium labelled antibodies analysed by ICP-MS. Before the proteins were quantified simultaneously, albumin and IgG concentrations were measured separately and compared to protein levels obtained by ELISA. It was found that protein concentrations for both albumin and IgG obtained with element-labelled antibody detection correspond to those determined by ELISA. Furthermore, albumin and IgG levels measured simultaneously by ICP-MS correspond to concentrations found when the proteins were analysed separately by ICP-MS. Finally, development of this method has provided a positive indication that it can be extended to quantification of additional proteins, which could be related to a disease or as a minimum provide additional information for a protein profile of an individual.