Development and validation of a NANOGold™ immunoassay for the detection of vascular endothelial growth factor (VEGF) in human serum using inductively coupled plasma mass spectrometry

This work aimed to develop and validate a NANOGold based assay, quantified using inductively coupled plasma mass spectrometry (ICP-MS), for the detection of human vascular endothelial growth factor (hVEGF) in serum. The initial assay range based on calibration standards was 62.5-2000 pg/mL with a detection limit of approximately 30 pg/mL. After validation using spiked validation controls, a quantification range between 175 and 1928 pg/mL was obtained. The inter-assay precision was between 2.3 and 18.9% with accuracy between -8.8 and -3.1%. Additional performance parameters, including dilutional linearity, matrix specificity and time-factored drift, were within +/-20%, as defined by the validation acceptance criteria for the validation of macromolecule immunoassays used within our clinical environment. Serum samples from healthy donors were analysed to determine the endogenous levels of VEGF present; these ranged from 164 to 580 pg/mL with a mean of 273 pg/mL. The intra- and inter-assay precision obtained from the healthy donor samples were 1.3-10.7% and 4.2-17.5%, respectively. This demonstration of a validated immunoassay opens further possibilities, utilising the simultaneous detection capabilities of ICP-MS for the detection of multiple analytes in a single validated immunoassay, for routine use within a clinical environment.