To characterize the selectivity of the proposed immunosensor, several proteins and cancer makers including alpha-fetoprotein (AFP), Tau protein (Tau), hemoglobin (Hb), L-cysteine (L-Cys) and L-glutamate (L-glu) at 10 ng mL−1 are used as potential interferences to evaluate the specificity through the comparison of the impedance response of 10 ng mL−1 CEA. This evidence concerns the gene AFP and cancer.