Surface immunoassays (e.g. ELISA, lateral flow) are the gold standard in clinical and point-of-care diagnostics. In contrast to detection of nucleic acid sequences, where amplification methods can be used, detection of proteins must rely solely on the initial concentration of targets in the sample. Therefore, at low target concentrations, immunoassays are limited by the slow binding kinetics between targets and antibodies. We here demonstrate the use of isotachophoretic focusing for acceleration of antibody-protein binding kinetics, improving the limit of detection (LoD) by 50 to 100 fold as compared to standard immunoassays.