Multicenter evaluation of a new progastrin-releasing peptide (ProGRP) immunoassay across Europe and China

Background: We performed a multicenter evaluation of the Elecsys(R) progastrin-releasing peptide (ProGRP) immunoassay in Europe and China. Methods: The assay was evaluated at three European and two Chinese sites by imprecision, stability, method comparison and differentiation potential in lung cancer. Results: Intermediate imprecision across five analyte concentrations ranged from 2.2% to 6.0% coefficient of variation. Good stability for plasma and serum samples was shown for various storage conditions. There was excellent correlation between the Elecsys(R) and ARCHITECT assays in plasma (slope 1.02, intercept -2.72 pg/mL). The Elecsys(R) assay also showed good correlation between serum and plasma samples (slope 0.93, intercept 2.35 pg/mL; correlation coefficient 0.97). ProGRP differentiated small-cell and non-small-cell lung cancer (NSCLC; area under the curve 0.90, 95% CI 0.87-0.93; 78.3% sensitivity, 95% specificity; at 84 pg/mL), with no relevant effects of ethnicity, age, gender or smoking. Median ProGRP concentrations were low in benign diseases (38 pg/mL), other malignancies (40 pg/mL) or NSCLC (39 pg/mL), except chronic kidney disease above stage 3 (>100 pg/mL). Conclusions: Increased stability of the Elecsys(R) ProGRP assay in serum and plasma offers clear benefits over existing assays. This first evaluation of a ProGRP assay in China demonstrated comparable differentiation potential among different ethnicities. (C) 2014 The Authors. Published by Elsevier B.V.