Critical role of the sample matrix in a point-of-care protein chip for sepsis

► On-chip sandwich assays for detection of IL-6 and PCT as biomarkers for inflammation and sepsis. ► Analyte detection in neat and diluted serum, plasma, and saliva. ► Interference testing with fluorescently labeled antibodies to matrix proteins. ► Matrix proteins bind unspecifically to the immobilized receptors with minor influence on the assay sensitivity.