This work presents a low‐cost, reagent‐free point‐of‐care biosensor integrating redox‐active polyphenol red molecularly imprinted polymers (pPhR MIPs) on highly porous gold (HPG) electrodes for ultrasensitive detection of phosphorylated tau 181 (p‐Tau 181), an Alzheimer’s disease biomarker, in undiluted biofluids. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.