Sensitivity and reproducibility improvements in a human plasma immunoassay with removal of clotting factors

摘要: Abstract Interferences in human plasma immunoassay are severe challenge that affects the sensitivity and reproducibility of assay. The clotting factor fibrinogen is a negatively charged protein one most common sources interference immunoassays, its removal increases reproducibility. Here, we present highly sensitive reproducible method for detection prostate specific antigen (PSA) immunoassays. Protamine sulfate, positively protein, was used to precipitate via ionic interaction improve immunoassay. In sandwich ELISA PSA using protamine-treated samples, limit improved from 413 pg/mL 235 pg/mL coefficient variation known as measure significantly lowered by protamine treatment. use sulfate immunoassays quartz crystal microbalance (QCM) biosensors resulted increased about 2-fold 3-fold, respectively, relative when not sulfate. Based on these results, best choice increase samples.