We present the development of a novel point-of-care electrochemical immunosensor for the detection of the Epstein–Barr virus capsid antigen (EBVCA-IgA) using a biocarbon-modified screen-printed electrode platform. The biosensor achieves sensitive and rapid detection within a broad linear range of 0.1 pM to 10 nM of EBVCA-IgA, with an impressive limit of detection of 33 fM. The key to its practical utility is that the sensor operates efficiently, providing results in under one hour, which is a significant improvement over traditional methods such as enzyme-linked immunosorbent assays and polymerase chain reaction that typically exceed two hours. We also emphasize the sensor’s high selectivity by demonstrating minimal cross-reactivity with other common respiratory viruses. With its combination of rapidity, sensitivity, and simplicity, this biosensor represents a significant advancement in Epstein–Barr virus (EBA) diagnostics, which makes it particularly beneficial in clinical and low-resource settings where rapid and reliable testing is paramount.